Stepmill

ABSTRACT

A stair climbing machine includes a plurality of steps connected, via a drive assembly, to, the frame of the machine to move in a closed loop path which brings each step to a position near the ground to provide a low step-on height. The drive assembly may optionally be supported on a movable portion of the frame to allow the incline of the closed loop path to be selectively varied to adjust the vertical distance between adjacent steps of the machine.

FIELD

The present disclosure relates generally to a stationary exercise machine and more specifically a stair climber machine.

BACKGROUND

Stair climber or stepper machines, also referred to as stepmills, are stationary exercise machines that simulate the motion of climbing stairs and thus can be used to exercise various muscle groups including the glutes, quadriceps, hamstrings, and calf muscles. Stair climber machines can provide a low-impact workout, the intensity of which can typically be selected by the user and is typically adjusted by varying the resistance to rotation, and thus the amount of support, provided by the stair assembly against the weight of the user. To provide a continuous path of stairs to climb, a stepmill typically has a set of discrete step platforms (or simply steps) connected to one another, alternating with a step riser or kickplate between each step, to form a continuous loop which is routed around a set of upper and lower rollers of a drive system that moves the steps in a closed loop path. Each step is typically a continuous fixed surface or platform that is hinged, at its toe side and heel side, to two other fixed continuous platforms that serve as the kickplates between adjacent steps. Typically, in order to route the interconnected steps and kickplates around the rollers of the drive system, each individual fixed surface or platform (e.g., of the steps and kickplates) must be routed or rotated around the upper and lower rollers of the drive system so as to provide the continuous stair climbing path of the stepper.

While being adjustable with respect to resistance, existing stepmills, however, do not provide the ability to adjust the physical parameters of the stair climbing path. For example, the step heights of existing stepmills is typically fixed, which can make the workout too challenging for smaller/shorter users and make the workout insufficiently challenging for taller users. Often, this is due to the fact that existing stepmills have fixed-length step and/or kickplate platforms. Another disadvantage of many existing stepmills is a step-on height, which may be too tall and thus too intimidating or cumbersome for some users, such as shorter users, inexperienced users, or users with declined mobility (e.g., the elderly). Accordingly, designers and manufacturers of stair climber machines continue to seek improvements thereto such as to enhance the user experience.

SUMMARY

In various embodiments, a stair climber machine is disclosed. The stair climber machine (or stepmill) of the present disclosure may provide a lower step-on height than may be possible with existing stair climbing machines, and may optionally be incline-adjustable to enable a user to change the height between the steps.

A stair climbing machine is disclosed. In one example, the stair climbing machine includes a frame with a base and an upright frame movably coupled to the base. A plurality of steps are movably coupled to the upright frame to move in a closed loop path. A lift mechanism is operatively coupled to the upright frame to selectively change a position of the upright frame relative to the base to change a step-height of the plurality of steps.

In another example, a stair climbing machine includes a frame with a base and an upright frame. A plurality of steps are movably coupled to the upright frame to move in a closed loop path. The plurality of steps are spaced apart from one another such that individual steps do not contact one another as the steps move in the closed loop path. Each of the plurality of steps includes a supporting platform provided by a plurality of individual slats pivotally connected to one another to allow the step to transition, while moving along the closed loop path, between a flat configuration in which user-supporting surfaces of the slats are substantially co-planar and a bent configuration in which the user-supporting surfaces of at least two adjacent the slats are pivoted away from one another.

In another example, a stair climbing machine includes a base and first and second upright frames coupled to opposite sides of the base. A plurality of steps are positioned in a space defined between the first and second upright frames and movably coupled to the first and second upright frames to move in a closed loop within the space. Each step has a toe end constrained to move along a first closed loop path and a heel end constrained to move along a second closed loop path different from the first closed loop path and which crosses the first closed loop path, wherein the first closed loop path is defined by at least one flexible member routed around and engaged with a corresponding plurality of rotating disks, and wherein the second closed loop path is defined by a track system.

This summary is neither intended nor should it be construed as being representative of the full extent and scope of the present disclosure. The present disclosure is set forth in various levels of detail in this application and no limitation as to the scope of the claimed subject matter is intended by either the inclusion or non-inclusion of elements, components, or the like in this summary.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate examples of the disclosure and, together with the general description given above and the detailed description given below, serve to explain the principles of these examples.

FIG. 1 is an isometric view of a stepmill according to the present disclosure.

FIG. 2 is another view of the stepmill of FIG. 1, shown here without a shroud to expose components of the drive assembly.

FIG. 3 is a front view of the stepmill of FIG. 2.

FIGS. 4A-4C show partial isometric views of the stepmill of FIG. 2 three different incline positions.

FIG. 5 is another partial isometric view of the stepmill of FIG. 2.

FIG. 6 is a side view of a portion of the stepmill shown in FIG. 5.

FIG. 7 is an exploded view of a portion of the frame and drive assembly of the stepmill in FIG. 2.

FIGS. 8A-8C shows simplified views of different examples of lift mechanisms for a stepmill according to the present disclosure, such as the stepmill in FIG. 2.

FIGS. 9A and 9B are views of an individual step of the stepmill in FIG. 2.

FIG. 10 is an enlarged partial view of an upper portion of the drive assembly showing a bracket for coupling the step to the drive assembly of the stepmill in FIG. 2

FIG. 11 shows another example of a step for a stepmill according to the present disclosure such as the stepmill in FIG. 2.

FIG. 12 shows yet another example of a step for a stepmill according to the present disclosure, such as the stepmill in FIG. 2.

FIGS. 13A and 13B show a further example of a step for a stepmill according to the present disclosure, such as the stepmill in FIG. 2, shown in two different stages of articulation.

FIGS. 14A and 14B show yet another example of a step for a stepmill according to the present disclosure, shown in a configuration and an articulated configuration.

FIG. 15 shows a simplified illustration of another example of step shrouding for a stepmill according to the present disclosure, such as the stepmill in FIG. 2.

FIG. 16 shows a simplified partial view of yet another example of step shrouding for a stepmill according to the present disclosure, such as the stepmill in FIG. 2.

FIGS. 17A and 17B show simplified side views of the stepmill in FIG. 2 in two different incline positions to illustrated the movement of the four-bar linkages defined by the upright frame and handlebar assembly.

FIG. 18 is a partial isometric view of a stepmill according to further examples of the present disclosure.

FIG. 19A is a partial side view of the stepmill in FIG. 18.

FIG. 19B is another side view of a lower portion of the stepmill in FIG. 19A with the steps shown in a position further along the closed loop path of the steps.

FIG. 20 is a simplified illustration of a drive assembly for a stepmill with fixed steps in accordance with further examples of the present disclosure.

FIG. 21 is a simplified illustration of a drive assembly for a stepmill with fixed steps in accordance with yet further examples of the present disclosure.

FIGS. 22A-22C are enlarged partial views of an upper portion of a drive assembly for a stepmill with fixed steps, like the stepmill in FIG. 21.

FIG. 23 is an enlarged partial side view of a lower portion of a drive assembly for a stepmill with fixed steps, like the stepmill in FIG. 21.

FIG. 24 is a perspective view of a fixed-step stepmill according to the present disclosure, viewed from the front side towards the rear side of the stepmill.

FIG. 25 is a front perspective view of the stepmill in FIG. 24.

FIG. 26 is another perspective view of the stepmill in FIG. 24, viewed from the rear side towards the front side of the stepmill.

FIG. 27 is a partial isometric view of the stepmill in FIG. 24 showing a portion of the frame and drive system of the stepmill.

FIGS. 28A and 28B show an isometric and a side view, respectively, of a portion of the drive system of the stepmill in FIG. 24 that is located on one side of the stepmill.

FIGS. 29A and 29B show an isometric and a front view of an individual step of the stepmill in FIG. 24.

FIG. 30 is a partial front view of components of the stepmill in FIG. 24.

FIG. 31 is a simplified view showing the closed loop paths traversed by the toe ends and heel ends of the steps of the stepmill of FIG. 24.

FIGS. 32A-32D show an enlarged partial view of the upper portion of the drive system of the stepmill of FIG. 24, with the steps positioned at a different position along the closed loop path in each of the views in FIGS. 32A-32D.

FIGS. 33A and 33B show an enlarged partial view of the lower portion of the drive system at two different inclined positions of the stepmill of FIG. 24.

FIG. 34 is another view of a portion of the stepmill in FIG. 24, showing a resistance mechanism for resisting the movement of the steps.

The drawings are not necessarily to scale. In certain instances, details unnecessary for understanding the disclosure or rendering other details difficult to perceive may have been omitted. In the appended drawings, similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a letter that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label. The claimed subject matter is not necessarily limited to the particular examples or arrangements illustrated herein.

DETAILED DESCRIPTION

Embodiments of the present disclosure are directed to an exercise machine, which is configured to simulate stair climbing motion, and is referred to herein as a stair climbing exercise machine or simply stair climber or stepmill. The stepmill may include a frame, which includes a base that supports the stepmill (e.g., by placing the base) on a support surface (e.g., the floor or ground). The stepmill includes a plurality of steps that are movably supported by the frame. The steps are operatively connected to one another to move in a closed loop path. The movement of one of the steps, e.g., responsive to a force applied by a user such as the user placing some or all of his weight on the step, is transmitted to the other steps via a drive system, which operatively connects the steps to cause them to move in the closed loop path. Embodiments of a stepmill according to the present disclosure may provide for a lower step-on height than previously possible by existing stair climbing machines. This may be achieved in a variety of ways as described further below. For example, a lower step-on height may be achieved by utilizing modular articulating steps that wrap around guide disks (e.g., pulleys or rollers, sprockets, or the like) of a drive system as they traverse the closed loop path. The individual modular articulating steps may be formed of multiple interconnected segments (e.g., slats) that articulate relative to one another about at least one degree of freedom. By utilizing articulating steps, rather than single-platform (or fixed) steps in some embodiment, the diameter of at least the lower guide disks of the drive system may be smaller than those of existing stepmills, allowing the lower end of the closed loop path to be brought closer to the ground to reduce the step-on height. In some embodiments, a fixed (non-articulating) step surface may be used. In some such embodiments, instead of routing the fixed step around guide disks, each of the fixed steps is flipped under and over the lower and upper guide disks, respectively, as they move from the front to the rear side of the closed loop path and vice versa. In such embodiments, the user-supporting surface of each of the fixed steps remains substantially facing the user while the step traverses the front and rear sides of the closed loop path.

In some embodiments, a portion of the frame of the step mill may be adjustable to allow the user to vary certain physical parameters of the stepmill, for example the vertical distance between the steps (i.e. the step height). The vertical distance between the steps may be adjusted, for example by changing the incline angle of the closed loop path. The steps may be supported at their opposite lateral ends by a respective lateral or side sub-frame, which may form a four-bar linkage. As such, in some embodiments of the stepmill, the incline angle of the closed loop path, and thus the step height, may be adjusted by articulating the four-bar linkages that support the steps. The four-bar linkage may be a planar quadrilateral linkage that includes four links and four pivotal joints. Each of the four links of the four-bar linkage may be of fixed length and the links may be operatively coupled to define a generally parallelogram shape. The four-bar linkage may include a fixed link, the position of which remains fixed with respect to a reference frame (e.g., the base of the machine), and three movable links that move relative to the reference frame for adjusting the incline angle of the closed loop path of the steps.

FIGS. 1 and 2 show isometric views, with and without shrouding, respectively, of a stair climbing exercise machine 10, interchangeably referred to as stepmill 10, and FIG. 3 shows a front view of the stepmill in FIG. 2. The stepmill 10 includes a frame 20 and a plurality of steps 50 movably supported by the frame. The frame 20 includes a base 21, which in use, supports the stepmill on a support surface (e.g., the ground or floor). The steps 50 are movably coupled to the base 21 via a drive assembly 30 that enables the steps to move in a closed loop path. The steps 50 may be equally spaced along the circumferential length of the closed loop path. Depending on the circumferential length of the closed loop path, any suitable number of steps may be used, e.g., 7 steps as in the present example (only the three steps on the user-facing side are shown in FIG. 1, while the 4 steps on the under- or rear-side of the path are removed from the view but would be arranged essentially edge to edge substantially continuously along the underside of the path). Having at least 3 steps minimum, at any given time, on the user-facing side in a configuration to support a user's foot may be useful in providing the ability to perform a “double step” or lunge exercise in which the user essentially skips a step when using the stepmill 10. In other embodiments, the stepmill 10 may have fewer steps, for example 6, 5 or fewer, or it, may have more than 7 steps (e.g., 8 steps, 9 steps, or more).

The base 21 of the stepmill 10 may be provided by one or more rigid members (e.g., any suitable combination of beams and/or a solid platform) arranged to provide a stable support structure for supporting the stepmill 10 onto the support surface. For example, the base 21 may include one or more longitudinal beams 22 extending between the front and rear sides of the stepmill 10, and one or more cross-beams 24 extending transversely, optionally perpendicularly, to, and in some cases between and/or connecting, the longitudinal beams 22. Without intending to be limiting, and solely for the ease of describing the components and operation of the stepmill 10 and to facilitate an understanding of the present disclosure, the side of the stepmill 10 facing the user during normal use of the stepmill 10 will be referred to as the front side 11, while the side facing away from the user during normal use will be referred to as the rear side 15. Components located closer to the respective front or rear side may thus also be referred to as front or rear components. Also for ease of illustration, the side and thus components located near the supporting surface (e.g., ground) during normal use of the machine, may be described as lower or bottom, while the side of the machine, and thus the components, farther away from the base and ground may be described as upper or top. Movement or components away or spaced from the mid-plane of the machine may be described as lateral.

In FIGS. 1-3, and referring also to FIGS. 4A-4C, the base 21 may include a pair of longitudinal beams 22 a and 22 b, which may extend substantially along the opposite lateral sides of the stepmill 10. In some embodiments, the beams 22 a and 22 b may be substantially parallel to one another and may define a base having a substantially rectangular footprint. One or more cross-beam 24 may extend transversely to the longitudinal beams 22 a and 22 b, in some cases connecting the longitudinal beams 22 a and 22 b. In some embodiments, the cross-beam(s) 24 may be positioned at a location rearward of the front side 11 of the stepmill 10 so as to not interfere with the movement of the step 50 or the user, if standing close to the front of the stepmill. In other embodiments, the arrangement of the longitudinal beams 22 a and 22 b and/or cross-beam(s) 24 may be different as long as they provide a stable base 21 for the machine. In some embodiments, the base 21 may be a substantially solid platform, or it may be at least partially provided by a platform. In some embodiments, the longitudinal beams 22 a and 22 b may extend at other angles from the front to the rear side of the stepmill, for example they may be angled, forming a base 21 that has a substantially V-shaped footprint, and X-shaped footprint, or other.

The base 21 supports a plurality of support members extending upwardly from the base 21, and collectively referred to as upright frame 40. The upright frame supports at least some of the components of the drive assembly 30, which connects the steps 50 into a closed loop path. The upright frame includes two lateral or side portions, specifically a first lateral (e.g., left) frame portion 40 a and a second lateral (e.g., right) frame portion 40 b, each located on opposite sides of a mid-plane of the exercise machine 10. The terms first and second, when referring to the sides of the exercise machine 10, may be interchanged with “left” and “right,” respectively, for simplicity and clarity of the description that follows, noting, however that this is not intended as limiting given that the designation of sides of the machine as either left or right is arbitrary and purely illustrative.

Each of the lateral frame portions 40 a and 40 b includes one or more movable members. The movable frame members are configured to move relative to the base 21 in a controlled manner (e.g., selectively, responsive to a selection by the user) for adjusting the incline of the stepmill 10, and consequently adjusting a physical parameter of the step assembly such as the step height H_(S) provided by the stepmill 10. In the context herein the step height H_(S) is defined as the vertical distance between the user-supporting sides of two adjacent steps 50 when located in the front side 11 of the stepmill 10, and thus positioned to face the user and support a user's foot. Each of the first and second lateral frame portions 40 a and 40 b may include a plurality of rigid members (e.g., links 42, 44, and 46), one or more of which are selectively movable relative to the base 21 for adjusting the incline of the stepmill 10. For example, each of the first and second lateral frame portion 40 a and 40 b may be configured as a four-bar linkage 41, specifically a first (or left) four-bar linkage 41 a and second (or right) four-bar linkage 41 b.

Each of the four-bar linkages 41 includes a first link 42, a second link 44, and a third link 46, each of which is movable relative to the base 21 and may thus be interchangeably referred to as first, second, and third movable or moving links 42, 44, and 46, respectively. In some embodiments, the first, second, and third links 42, 44, and 46, respectively, may be movably coupled to the respective one of the longitudinal beams (e.g., the left beam 22 a or the right beam 22 b). Each of the first link 42, second link 44, and third link 46 may be implemented using any suitable rigid member, such as a tube or differently shaped beam (e.g., a structural member capable of carrying the relevant loads such as bending, compression and tension). One end 42-1, also referred to as lower end 42-1, of the first link 42 is non-rigidly (e.g., pivotally) coupled to the respective longitudinal beam (e.g., left beam 22 a), at a first location 47 along the length of the beam is rotatable about a first pivot axis A₁. The first link 42 has an end 42-2 opposite the end 42-1, also referred to as upper end 42-2, of the first link 42. Similarly, one end 44-1, also referred to as lower end 44-1, of the second link 44 is non-rigidly (e.g., pivotally) coupled to the respective longitudinal beam (e.g., left beam 22 a), at a second location 45 spaced apart from the first location 47, thereby positioning the link 44 in a spaced apart relationship with the first link 42. The lower end 44-1 of the second link 44 is pivotable about a second pivot axis A₂ spaced apart from and parallel to the first pivot axis A₁. The first link 44 has an end 44-2 opposite the end 44-1, also referred to as upper end 44-2, of the first link 44.

The first link 42 is coupled to the base 21 relatively closer to the front side of the stepmill 10 as compared to the second link 44 and may thus be referred to as front link 42 while the second link 44 may be referred to as a rear link 44. A third link 46 connects the upper ends 42-2 and 44-2 of the first and second links 42 and 44, respectively. One end 46-1 of the third link 46 is pivotally coupled to the upper end 42-2 of the first link and the opposite end 46-2 of the third link 46 is pivotally coupled to the upper end 44-2 of the second link 44. The pivotal connection between the third link 46 and the first link 42 defines a third pivot axis A₃ and the pivotal connection between the third link 46 and the second link 44 defines a fourth pivot axis A₄. The third pivot axis A₃ is movable (e.g., pivotable) about the first pivot axis A₁ and the fourth pivot axis A₄ is movable (e.g., pivotable) about the second pivot axis A₂.

A fourth link 48, which remains substantially fixed relative to the base 21 and is thus also referred to as fixed link 48, is defined between the lower ends 42-1 and 44-1. The fixed link 48 may be defined by two locations on the frame 20 that remain in a fixed relationship at all times. For example, the fixed link 48 may be defined by the spaced apart pivotal mounting locations of the lower ends of the first and second links. The fourth link 48 may thus have a length substantially defined by the distance between the first and second locations 47 and 45 (see, e.g., FIG. 4A). In some embodiments where a separate or distinct link member is not used for the fixed link, the fixed link may also be referred to as a virtual link. In some embodiments, optionally, a separate or additional rigid member 49, such as a tube or other type of beam, may be connected between the lower ends 42-1 and 44-1 of the first and second links 42 and 44, respectively, to provide, in part, the function of the fixed link 48. The rigid member 49 may connect the pivotal joints of the first and second links which may improve the stability of the four-bar linkage such as by substantially reducing freeplay or relative movement between the pivotal joints of the first and second links.

A drive assembly 30 movably couples the steps 50 of the stepmill 10 to the frame 20. The drive assembly 30 includes a first (e.g., left) drive sub-assembly 30 a and a second (e.g., right) drive sub-assembly 30 b. The first (e.g., left) drive sub-assembly 30 a is associated with the first (e.g., left) lateral frame portion 40 a, and the second (e.g., right) drive sub-assembly 30 b is associated with the second (e.g., right) lateral frame portion 40 b. In some embodiments, each of the first and second drive sub-assemblies 30 a and 30 b may include substantially the same set of components, mirrored across the mid-plane of the exercise machine 10 and arranged to operate in a like manner to support and route the respective (e.g., the left or right) sides of the steps 50 along their closed loop paths. The drive assembly 30 may be implemented using any suitable combination of components that can substantially constrain the movement of the steps 50 along a desired closed loop path. For example, the drive assembly 30 may be implemented using a chain drive, a belt drive, a geared drive, or other suitable drive components or combinations thereof. The drive assembly 30 may be configured to transmit rotation from one rotatable component (e.g., a guide disk) to another rotatable component such as via a flexible member (e.g., a belt or chain), thereby interconnecting the plurality of steps 50 to move together in a closed loop path. In some embodiments, the drive assembly 30 may, additionally or alternatively, utilize one or more track and corresponding engagement members (e.g., rollers, sliders, etc.) configured to engage the track(s) to follow a path defined by the track(s).

As shown in FIGS. 4A-4C, each of the left and right drive sub-assemblies 30 a and 30 b includes a respective pair of flexible members (e.g., which may be implemented using cables, belts, ropes, chains, or the like), specifically a first pair of flexible member 36 a and 38 a, and a second pair of flexible members 36 b and 38 b. Each of flexible members on a given side of the machine is provided as a continuous or closed loop around a plurality of corresponding rotating guide members or disks (e.g., pulleys, drums, rollers, sprockets, or the like) to define the respective closed-loop path traversed by either the heel end 60-2 or toe end 50-1 of each step 50. The term flexible, when describing a flexible members, means that the flexible member is bendable such as to enable it to route or wrap around a rotating guide member. As such, the flexible member may be used to transmit force in tension, for example to transmit the rotation of one guide member to the next, without transmitting force in compression. With reference also to FIGS. 5-7, which show the right drive sub-assembly 30 b, the pair of flexible members on a given side of the machine includes a first (or inner) flexible member 38 and a second (or outer) flexible member 36. Each of outer and inner flexible members 36 and 38, respectively, are associate with a respective set of rotating disks, also referred to as guide disks, whereby the rotation of one of the guide disks may be transmitted to and/or synchronized with rotation of another guide disk. Each of the outer and inner flexible members 36 and 38, respectively, is configured to engage (e.g., through chain and sprocket interaction or a belt/cable and drum/pulley frictional interaction) corresponding rotatable guide disks to couple the rotation of one guide disk to at least one other guide disk. In some embodiments, the rotation of the guide disks may optionally be coupled to another rotating member (e.g., a disk or shaft), the rotation of which may be resisted by any suitable resistance mechanism 90, such as a friction brake, a magnetically resisted brake or air-brake, for resisting the movement transmitted by the drive assembly 30. In some embodiments, one or more idler disks 31 (e.g., idler pulley(s) or sprocket(s)) may be arranged along the paths defined by the flexible members to ensure sufficient tension is maintained along the length of the flexible members to transmit motion from one element to another.

Each of the outer and inner flexible members 36 and 38, respectively, on a given lateral side of the machine 10, is associated with a corresponding set of rotating guide members (e.g., outer and inner guide disks 32 and 34, respectively). The guide disks 32 and 34 are rotatably supported on the frame. In some embodiments, each of the guide disks 32 and 34 may be rotatable about a shaft which is aligned with one of the four pivot axes A₁, A₂, A₃, and A₄ of the four-bar linkages 41. A first set of guide disks, referred to as first or inner guide disks 34, are arranged to lie substantially in a first (or inner) plane D_(I) (see FIG. 2). The inner guide disks 34 define the closed loop path for the inner flexible member 38, which is also referred to as the inner loop P_(I) (see FIG. 7). A second set of guide disks, also referred to as second or outer guide disks 32, are arranged to lie substantially in a second (outer) plane D_(O) (see FIG. 3) and provide a closed loop path for the outer flexible member 36, also referred to as outer loop P_(O) (see FIG. 7). As such, the first and second guide disks lie in two different, laterally spaced planes. The second (or outer) guide disks 32 are arranged, relative to the first (or inner) guide disks 34 on the same side of the machine, in a plane which is laterally outward from the plane of the first guide disks 34. As shown in FIGS. 3 and 10, the inner plane D_(I) may be parallel to laterally inward (i.e., relatively closer to the mid-plane of the machine) from the outer plane D_(O). The inner and outer planes D_(I) and D_(O) and, correspondingly, the inner and outer flexible members 38 and 36 are located on opposite sides of at least one frame member of the respective four-bar linkage 41, for example on opposite sides of the first link 42 or the second link 44, or on opposite sides of both the first and second links 42 and 44.

Each of the outer and inner loops P_(O) and P_(I), respectively, may be defined by a respective plurality of guide disks. For example, a plurality of (e.g., four) outer guide disks 32 may be used to define the outer loop P_(O) that has a generally quadrilateral shape. In such embodiments, all of the outer guide disks 32 may be located inside the outer loop P_(O), e.g., with each of the guide disks 32 positioned at one of the four corners of the loop P_(O). The outer flexible member 36 is arranged in a continuous closed loop around the four guide disks 32. In some embodiments, the outer guide disks 32 may be arranged such that the pivot axis of each of the four outer guide disks 32 aligns or coincides with one of the four pivot axes of the four-bar linkage 41. The outer loop P_(O) may have a generally quadrilateral shape (e.g., a rhomboid in some incline positions) which may substantially corresponds to the shape of the four-bar linkage 41. The outer loop P_(O) may be defined by an outer flexible member 36 wrapped around four outer disks 32-1 through 32-4. In some embodiments, the outer guide disks 32 may be arranged such that the pivot axis of each of the four outer guide disks 32 aligns or coincides with one of the four pivot axes of the four-bar linkage 41. For example, a first (or front lower) outer disk 32-1 may be rotatably coupled to the frame 20 via a front lower shaft 33-1, which extends along and rotates about the pivot axis A₁ associated with the first link 42. A second for rear lower) outer disk 32-2 may be rotate coupled to the frame via a rear lower shaft 33-2 which extends along and rotates about the pivot axis A₂ associated with the second link 42. A third (or front upper) outer disk 32-3 may be pivotally supported on a front upper shaft 33-3 that rotates about the pivot axis A₃ associated with a pivot joint between the first and third links 42 and 46, respectively. A fourth (or rear upper) outer disk 32-4 may be pivotally supported on a rear upper shaft 33-4 that rotates about the pivot axis A₄ associated with a pivot joint between the second and third links 44 and 46, respectively.

The inner and outer closed loops defined by the inner and outer flexible members may be differently shaped. For example, the inner loop P_(I) may have an L-shape, including a substantially horizontal loop portion P_(I-1) that extends along the length of one of the horizontal links (e.g., the fixed link 48), and a vertical loop portion P_(I-2) that extends upward from, but not necessarily perpendicularly to, one end of the horizontal loop portion P_(I-1). The outer loop P_(I) may be defined by a plurality of outer guide disks 34, which may also be located near the corners of the four-bar linkage 41. To define a generally L-shaped path, three of the inner guide disks 34 may be positioned inside the loop P_(I), and a fourth inner guide disk 34 may be positioned outside of the loop P_(I) at the interface or transition from the horizontal loop portion P_(I-1) to the vertical, loop portion P_(I-2). One or more of the inner guide disks 34 may be positioned coaxially with a pivot axis of the four bar linkage 41. For example, a first (or front lower) inner disk 34-1 may be rotatably coupled to the frame via a corresponding shaft 35-1, which in some embodiments may be the same shaft or a shaft coaxially aligned with the front lower shaft 33-1 that couples the outer disk 32-1 to the frame. A second (or rear lower) inner disk 34-2 may be rotatably coupled to the frame via a corresponding shaft 35-2, which in some embodiments may be the same shaft or a shaft coaxially aligned with the rear lower shaft 33-2 that couples the outer disk 32-2 to the frame. A third inner disk 34-3 may be located near the second inner disk 34-2 but spaced apart from the inner disk 34-2 (e.g., diagonally towards the front upper corner of the four-bar linkage) to constrain the route of the inner flexible member 38 into an L-shape. The inner disk 34-3 may be rotatably coupled to the frame via a shaft 35-3 which may be parallel to but may not coincide with any of the pivot axes A₁-A₄ of the four bar linkage. A fourth (or rear upper) inner disk 34-4 may be rotatably coupled to the frame via a shaft 35-4, which may be the same or coaxial with the upper rear shaft 33-4 that couples the outer disk 32-4 to the frame. In some embodiments, inner and outer guide disks that are coaxially arranged may rotate in synchrony with one another. For example, the inner and outer front lower disks may rotate in synchrony with one another, the inner and outer rear lower disks may rotate in synchrony with one another and/or the inner and outer rear upper disks may rotate in synchrony with one another. In some embodiments, all of the guide disks on a given side (e.g., the left side or the right side) may rotate in synchrony. In some embodiments, all of the guide disks on both sides of the machine may rotate synchronously.

During normal use of the stepmill, when a user's foot is supported on a step 50, the user's toes are located near the first longitudinal side 50-1 of the step 50, also referred to herein as the toe end 50-1 of the step, and the user's heel is located near the second longitudinal side 50-2 of the step 50 opposite the first longitudinal side 50-1 and which is also referred to as the heel end 50-2 of the step. The steps 50 may be arranged with respect to the frame 20 such that the first and second sides of each step are adjacent a respective one of the first and second upright frame portions 40 a, 40 b, with the step 50 being generally suspended between the two upright frame portions. The steps 50 may be coupled to the stepmill 10 via mounting components extending laterally outward from the first and second lateral sides 50-3 and 50-4, respectively, of the step 50 toward a respective one of the first and second upright frame portions 40 a and 40 b, respectively. The toe end 50-1 of each step is operatively coupled, at each of its opposite lateral sides 50-3 and 50-4, to a respective one of the flexible members 36 a and 36 b, both of which define respective continuous loops of substantially the same shape, and thus the toe ends 50-1 of the steps are substantially constrained to traverse a first closed loop path, as defined by the flexible members 36 a and 36 b. The heel end 50-2 of each step is operatively coupled, at each of the opposite lateral sides 50-3 and 50-4 of the step, to a respective one of the flexible members 38 a and 38 b, both of which define respective continuous loops having substantially the same shape, and thus the heel ends 50-2 of the steps are substantially constrained to traverse a second closed loop path, as defined by the flexible members 38 a and 38 b. The combined movement of the toe ends 50-1 along the first closed loop path and the heel ends 50-2 along the second closed loop path define an overall closed loop path for the steps 60 of the stepmill 10. In other embodiments, the connection may be reversed, that the toe ends 50-1 of the steps 50 may be connected to the outer flexible member 3 while the heel ends 50-2 of the steps 50 may be connected to the inner flexible member 38.

In some embodiments, the heel ends 50-2 of each step 50 may be connected to the outer flexible members via brackets 51 that are suitably shaped (e.g., U-shaped) to pass over the inner flexible member, and thus through the inner plane D_(I), without interfering with the movement of the inner flexible member 38 along its closed loop path. The brackets 51 may be formed of a material (e.g., a metal, a substantially rigid plastic or composite material, or other) which is sufficiently strong to support the heel end 50-2 of the step 50, with or without the user's weight thereon. In other embodiments, and depending on the configuration of the drive assembly, the brackets 51 may be differently shaped, such as substantially L-shaped, for example in embodiments in which larger diameter guide disks are used for the outer loop than for the inner loop.

Referring now also to FIGS. 9A and 9B, each of the steps 50 may be configured multi-piece, which are configured to articulate or at least partially wrap around the curvature of the guide disks when traversing their closed loop paths. Such steps may be referred to herein as articulating steps. Each step 50 may include a plurality of individual and operatively connected slats 53 that provide a foldable or articulating step platform 52. The plurality of individual operatively connected slats 53 allows each step platform 50 to transition, as it traverses the closed-loop path, between a flat configuration, e.g., when positioned on the user-facing side of the machine or when traversing the underside of the closed loop path, and a compact or curved configuration, e.g., when passing over a guide disk. The individual slats 53 may be formed from any suitable material(s), for example extruded or otherwise formed metal slats, sufficiently rigid plastics (e.g., PC/ABS blend, Nylon, or various blends of Nylon including 5% glass fill (“GF”), 30% GF, or other), or any suitable composite material (e.g., a fiber re-enforced composite material, combinations of metal coated or otherwise at partially encased with plastic, etc.). The slats 53 may extend continuously along the length L of each step 50, between the third (e.g., left) and fourth (e.g., right) sides 50-3 and 50-4, respectively of the step 50. Adjacent slats 53 may be operatively (e.g., pivotally) connected to allow for the slats 53 to articulate (e.g., move or pivot) with respect to one another. Any suitable pivotal coupling between adjacent slats 53 may be used that can provide a stable supporting platform for the user's foot when the step 50 is in the flat configuration. The step platform 52 may be implemented using any suitable number of slats, for example two slats as shown in FIGS. 14A and 14B, or more than two slats, such as three, four or more slats. For example, the step platform may include five slats as in the examples in FIGS. 11, 12, and 13A-13B, six slats as in the example in FIGS. 9A and 9B, or more slats, if desired. In some embodiments, one or more of the slats 53 may differ in width W_(S) from one or more of the other slats, e.g., as shown in FIGS. 9A and 9B. In other embodiments, each of the slats may have substantially the same width.

The step 50 may be mounted to the drive assembly 30 via a set of first (or toe end) mounts 56 a and 56 b, which couple the first side (or toe end) 50-1 of the step 50 to the drive assembly 30. A set of second (or heel end) mounts 54 a and 54 b couple the second side (or heel end) 50-2 of the step 60 to the drive assembly 30. Each of the first mounts and second mounts may be fixed to (e.g., rigidly coupled or integrally formed with) the step platform 52 so as to extend from a lateral side (e.g., the third side 50-3 or fourth side 50-4) of the step 50. The first mounts 54 a and 54 b may be fixed to the toe-end slat 53-h and the second mounts 56 a and 56 b may be fixed to the heel end slat 53-t. The mounts may be configured to pivotally coupled the toe end and the heel end of the step to the respective flexible member. For example, each of the first mounts may include a housing 59-1, such as a tube having a cylindrical cavity, that pivotally receives a first pin 55-1. Each of the second mounts may similarly include a housing 59-2 that defines a cylindrical cavity to pivotally receive a second pin 55-2. The pins 55-1 may be fixed, directly or using one or more intermediate components, to the inner flexible member 38 and the pins 55-2 may be fixed, directly or using one or more intermediate components (e.g., a bracket 51), to the outer flexible member 36. Any other suitable arrangement for pivotally coupling the toe ends and heel ends of the step to respective fixed locations along the respective flexible member may be used.

Adjacent slats 53 of a given step 50 may be pivotally connected, e.g., using a hinge 57 or other suitable pivot joint, to enable the step platform 52 to fold or articulate from the flat configuration in only one direction, which is referred as the articulation direction. One or more hinges 57 (e.g., a piano hinge or other suitable hinge) may be used to connect the undersides of adjacent slats 53 as shown in FIG. 9B. The opposing (e.g., interlocking or otherwise interfacing) faces of the adjacent slats may be configured to abut one another when the step is in the flat configuration, thereby substantially limiting or preventing rotation in the direction opposite the articulation direction, referred to here as over-rotation. In some embodiments, which may further limit or prevent over-rotation of the slats. Reducing or eliminating over-rotation may be helpful in providing a stable platform to support the user's foot. In some embodiments, a single pivot joint (e.g., a single hinge) may be provided along substantially the full length of the adjacent slats 53, which may result in a more stable or robust coupling between the adjacent slats. In other embodiments, a plurality of separate hinges may be used to couple two adjacent slats. The individual slats may be operatively configured and connected to provide a supporting platform 52 that can support at least 400 lbs. In some embodiments, the steps can support a greater amount of weight such as up to 500 lbs., up to 600 lbs., up to 700 lbs, or greater.

Multi-slat step platforms 152, 152′, and 152″ of steps 150, 150′, and 150″, respectively, according to further examples are shown in FIGS. 11, 12, and 13A, respectively. As in the example in FIG. 9A, the articulating step platform 152 is provided by a plurality of longitudinal slats 153 operatively connected to fold or articulate in a direction of articulation, indicated by arrow 161, from the flat configuration shown in FIG. 11 to a folded configuration (not shown). Adjacent slats 153 may be configured such that the step 150 is substantially restricted from rotating from the flat configuration in the direction opposite the direction of articulation 161. For example, the pivot axes 163 associated with the pivotal joints between adjacent slats 153 may be located relatively closer to the underside 164 of the step 150 that the user-supporting side 166, which may enable the adjacent slats 153 to rotate substantially freely or unimpeded in the articulation direction. The opposing faces 165 and 167 of adjacent slats 153 may be configured to abut one another and/or limit or prevent relative sliding between the two faces 165 and 167, which may limit or eliminate rotation in the direction opposite the direction of articulation 161. The faces 165 and 167 may be configured to extend substantially vertically (e.g., normal to the user-supporting side 166), as shown FIG. 11. In other examples, the faces 165 and 167 may be differently configured. In FIG. 12, the opposing 165 and 167 between each two adjacent slats 153′ may include cooperating (e.g., concave and convex, respectively) curved portions that may be slidable relative to one another when the slats are articulated in the direction of articulation 161. The faces 165 and 167 may be configured to reduce or eliminate the relative sliding between the two opposing faces, for example by arranging (e.g., orienting or otherwise positioning) the two sides such that they intersect the pivot axis 163, as shown in FIG. 13A. In some embodiments, as shown in FIGS. 13A and 13B, the rotation of the slats 153″ may also be limited in the direction of articulation 161 for example using an articulation liming feature 169 associated with the respective pivotal joint between two adjacent slats 153″.

FIGS. 14A and 14B illustrate another example of a multi-slat step 250 that includes a plurality of slats 253. The step 250 is configured as a two-piece step including a first slat 253-1 and a second slat 263-2. The two slats 253 are pivotally coupled at a pivot joint 269. In this example, the pivot axis 263 of the pivot joint 259 is positioned closer to the user-supporting side 266. Over-rotation is limited by a tension member 271, shown here as a rigid link 273. The rigid link 273 is pivotally connected to one of the slats (e.g., first slate 253-1) and movably connected to the other slat (e.g., second slat 253-2). The link 273 arranged below the pivot axis 263 such that the link 273 is closed to the underside 264 of the step 250 than the pivot axis 623. The link 273 is constrained to move (e.g., slidably or rollingly) along the depth direction of the step 250. As such, when the step 250 is in the fiat configuration (FIG. 14A), the rigid link 273 is loaded in tension to prevent the slats 235 from rotating in a direction opposite the articulation direction.

Referring back to FIGS. 2 and 4A-4C, the incline of the stepmill 10 may be adjusted by changing the position of the moving links of the four-bar linkages 41 a and 41 b relative to the base 21. For example, the incline of the stepmill 10 may be reduced (e.g., bringing the top of the closed loop path closer to the base) by moving the first, second and third links 42, 44, and 46 closer to the first link 48 and thus to the base 21. This causes the step height H_(S) to be reduced. Conversely, the incline of the stepmill 10 may be increased (e.g., positioning the top of the closed loop path farther away from the base 21) by moving the first, second and third links 42, 44, and 46 away from the fourth link 48 and base 21, thereby causing an increase in the step height H_(S). The incline of the stepmill 10, and thus the step height H_(S), may be selectively adjusted (e.g., by the user, in some cases while using the stepmill 10 to perform exercise), via any suitable lift mechanism 60, which is operatively associated with the upright frame 40, and more specifically with the first and second lateral frame portions 40 a and 40 b. In some embodiments, a single lift mechanism 60 may drive the movement of the moving links of both lateral frame portions 40 a and 40 b. In other embodiments, two or more separate lift mechanisms 60 may be used, each operatively engaged with the respective lateral frame portion to adjust the position of the respective set of links. In some such embodiments, the operation of the plurality of mechanisms 60 may be synchronized such that the left and right four-bar linkages move together, even when driven/adjusted by multiple separate lift mechanisms 60. In yet other embodiments, the force for raising and lowering the upright frame 40 may be applied by one or more lift mechanisms 80 to a portion of the upright frame 40 that connects the left and right four-bar linkages (e.g., cross-member 43 in FIG. 7).

The one or more lift mechanisms 60 may be implemented using any suitable lift motor or any suitable linear actuator. For example, the lift motor may include an electric motor operatively coupled to extend and retract an extendible member (e.g., a rod, such as a threaded rod). The lift motor may use a worm drive (e.g., a worm screw driven by worm wheel) to retract and extend the extendable member. In some embodiments, a hydraulic or other type of motor may be used instead of an electric motor. In some embodiments, the lift mechanism 60 may alternatively or additionally use a hydraulic or pneumatic cylinder or another type of linear actuator. In some embodiments, the incline may be adjusted using a lift mechanism 60 which pushes directly on a component of the upright frame 40 to lift and lower the moving components of the upright frame 40. For example, referring to FIGS. 2 and 4A-4C, one or more lift mechanisms 60 (e.g., lift motors 61) may be operatively coupled between the base 21 and the moving components of the upright frame 40 to apply a pushing force (e.g., responsive to an extension of the rod 63) on a component (e.g., one of the moving links 42, 44 or 46) of the four-bar linkage 41, which raises the four-bar linkage 41 relative to the base 21. Operated in reverse, the one or more lift mechanisms 60 (e.g., lift motors 61) may apply a pulling force (e.g., responsive to a retraction of the rod 63) on the component (e.g., one of the moving links 42, 44 or 46) of the four-bar linkage 41, thereby lowering the four-bar linkage 41 relative to the base 21. In other embodiments, the configuration (e.g., position) of the lift mechanism (e.g., lift motor 61) may be different so as to reverse the operation thereof, such as to obtain raising and lowering of the four-bar linkage responsive to a retraction and extension, respectively, of an extendible member (e.g., the rod 63).

In other embodiments, the lift mechanisms 60 may act indirectly on the upright frame 40. For example, referring to FIG. 8A, the lift mechanism 60 may be operatively coupled to the upright frame (e.g., to one or both of the four-bar linkages 41) via a cable and pulley system 66 which is operatively associated with a lift mechanism 60 (e.g., a winch or other rotating drum, rotatable manually or by a power source such as a motor) that applies a pulling force on a flexible member 67 (e.g., a cable, chain, rope or the like) of the cable and pulley system 66. In the illustrated example of a cable and pulley system, the flexible member 67 is anchored at one end to the frame 20 of the machine (e.g., via a first fixed (or anchor) pulley 66-1). The opposite end of the flexible member 67 is connected to the lift mechanism (e.g., a winch) which can pull the flexible member 67 away from the anchor point (e.g., anchor pulley 66-1). The flexible member is routed, in that order, around a floating pulley 66-2, which is rotatably connected to the upper link 46, and a second fixed pulley 66-3, which remains stationary relative to the frame 20, before the end of the flexible member is coupled to the lift mechanism 60. As such the position of the anchor pulley 66-1 and the fixed pulley 66-3 do not change relative to the frame when operating the lift mechanism 60, while the position of the floating pulley 66-2, and thus the position of the upper link 46, may be changed (e.g., moved up or down) by operation of the lift mechanism 60. When the lift mechanism 60 is operated in one direction (e.g., to pull the flexible member 67 away from the anchor point, the unwound length of flexible member 67 is reduced, raising the floating pulley 66-2 and thus raising the third (or upper) link 46 of the four-bar linkage 41 away from the base 21. When the lift mechanism 60 is operated in reverse, the floating pulley 66-2 is lowered thereby also lowering the upper link 46, bringing it closer to the base to decrease the incline angle A_(I) of the four-bar linkage 41 relative to the plane P_(S) defined by the base 21.

In other examples, the force for adjusting the incline of the stepmill 10 may be applied by the lift mechanism (e.g., a lift motor 61) indirectly to the four-bar linkage, such as via an intermediate link (e.g., a push link 65 in FIG. 8B). The push link 65 may be connected at one end 65-4 to one of the moving links of the four-bar linkage 41, for example the first link 42. In other examples, the push link 65 may instead be connected to, thus applying a force to, another one of the moving links, for example the second link 44 or the third link 46. The lift motor 61 may be connected to an opposite end 65-2 of the push link 65 such that extension of the extendible member 63 of the lift motor 61 pushes the driven end 65-2 of the push link 65 toward the four-bar linkage 41, raising the first end of the push link 65 and thus the four-bar linkage. The operation of the motor 61 may be reversed such that a retraction stroke moves the driven end away from the four-bar linkage (towards the rear of the machine) and thus brings the four-bar linkage 41 closer to the base 21, while an extension stroke moves the push link 65 forward causing the four-bar linkage 41 to be raised relative to the base 21. The driven end 65-2 of the push link 65 may be movably (e.g., rollably or otherwise slidably) supported on the base 21. The supported driven end 65-2 of the push link 65 may be constrained to move along a line (e.g., along the longitudinal direction such as by operatively coupling the driven end 65-2 to a slot 62 in the respective longitudinal beam of the base 21). While only one side of a stair climbing machine is shown in FIGS. 8A-8C, in some embodiments the same type of lift mechanism may be provided on the other side, and the pair of lift mechanisms may be synchronized and/or the push links may be tied together so that the left and right four-bar linkages raise and lower together. In this embodiment, each of the one or more lift motors 61 that drives the push link and thereby the raising and lowering of the four-bar linkage, may be arranged substantially horizontally (e.g., parallel to the supporting plane define by the base 21).

In other examples, and referring to FIG. 5C, the lift motor 61 may be differently oriented relative to the base 21, for example substantially vertically (e.g., perpendicularly) to the supporting plate of the base 21. In such embodiments, the force (e.g., to raise or lower the four-bar linkages) may be applied by the lift motor(s) using an intermediate push link 65′, which is differently constrained in movement relative to the frame. Like the push link 65 in FIG. 8B, the push link 65′ in FIG B is also coupled to the four-bar linkage 41 (e.g., to the first link 42, or to either one of the other moving links) at its first end 65-1′. The opposite end 65-2′ of the push link 65′, referred to as the driven end, is coupled to a lift motor 61 or any suitable lift mechanism via rocker link 64. The rocker link 64 may be pivotally coupled, at one end, to the extendable member 63 of the lift motor 61, and at its opposite end to the driven end of the push link 65-2′. As the first end of the rocker link 64 moves away from the lift motor 61 (e.g., through extension of the member 63), the driven end is pushed towards the front end of the machine, thereby raising the four-bar linkage 41. Conversely, as the first end of the rocker link 84 is brought closer to the lift motor 61, the driven end 65-2′ of the push link 65′ moves towards the rear side of the machine lowering the four-bar linkage 41. In some embodiments, the lift motor 61 may be differently positioned so as to reverse the resulting, movement of the rocker link 64 from the extension and retraction strokes of the lift motor 61. In some embodiments, the rocker link 64 and/or the driven end of the push link 65′ may be stabilized to the frame, such as to constrain their movement substantially in plane. For example, a first stabilizing link 68 may be pivotally coupled at one end to the rocker link 64 and/or the driven end of the push link. The first stabilizing link 69 may be operatively connected to the frame, such as through a pivotal connection to a fixed support link 69 that is rigidly supported by (e.g., fixedly coupled or integrally formed with) a component (a longitudinal beam) of the base 21.

In some embodiments, the incline of the stepmill 10 may be adjustable to a substantially horizontal position, as shown in FIG. 4C, which may be referred to as the zero-incline position. In such a position, the steps may form a substantially continuous support surface that is substantially flat or parallel relative to the base 21. The spacing between the steps 50 and/or dimensions of the individual steps 50 may be selected to provide such a substantially continuous support surface when the stepmill is in the zero-incline position. To enable lowering of the four-bar linkages 41, for example to a zero-incline position, some of the links (e.g., the first and third links 42 and 46) may lie in a different plane than (e.g., parallel to but offset from the plane of) the other links (e.g., the second and fourth links 44 and 48).

In some embodiments, the stepmill 10 may include protective shrouding, e.g., to conceal moving components of the stepmill such as to protect the user accidentally coming into contact with moving components and/or for aesthetics. For example, movable components of the stepmill 10, such as the moving frame portion (e.g., the upright frame 40) and the drive assembly 30, may be substantially enclosed or concealed by shrouding 12, such as to protect the user from coming into contact with these movable components during normal use of the stepmill 10. As shown in FIG. 1, the stepmill 10 may include left and right frame shrouds 13 a and 13 b, respectively. Each of the left and right frame shrouds 13 a and 13 b may be implemented as multi-part shrouds. The multi-part shroud on each side may include one or more individual shroud pieces (e.g., shroud pieces 13 a-1, 13 a-2, and 13 a-3) that move relative to one another to remain operatively positioned (e.g., for concealing the frame and/or drive assembly) during and after incline adjustments.

Additionally and optionally, the stepmill 10 may include step shrouding 14. During normal use of the stepmill 10, as the steps 50 travel along their closed loop path, the individual steps 50 may travel from the front side 11 (also referred to as the user-facing side) to the rear side 15 of the stepmill 10. The user-facing side 11 is the side of the machine that the user is facing during normal use of the stepmill 10 (e.g., for performing stair climbing exercise). The step shrouding 14 may be operatively positioned with respect to the steps 50 to protect or prevent the user's foot from crossing into the rear side 15 of the path of the steps 50. In some embodiments, the step shrouding 14 may be located substantially in a mid-plane or a plane parallel to the mid-plane between the front and rear sides of the closed loop path. In some embodiments, the step shrouding 14 may be implemented as multi-part shrouding, which includes individual step shrouds 14-i (see e.g., FIGS. 9A-9B), each of which is associated with an individual step 50 and may also function as a riser between adjacent steps. A step shroud 14-i may be configured in any suitable manner to substantially span the distance between two adjacent steps. For example, and referring to FIGS. 9A and 9B, a step shroud 14-i may be coupled to the heel end 50-2 of a step so that it hangs below the step 50 when the step 50 is positioned on the front side 11 of the stepmill 10.

The individual step shrouds 14-i may be implemented using a sheet of flexible material (e.g., fabric, polymer, composite or other). The sheet of flexible material may be operatively connected to each individual step, e.g., along the length of the heel end 50-2 of the step, such that it hangs below the step towards a lower adjacent step. The sheet of flexible material may be sufficiently long to substantially fully span the distance between two adjacent steps. In some embodiments, the sheet of flexible material may hang substantially vertically downward toward the lower adjacent step. In some embodiments, the sheet of flexible material may have a hanging length which is greater than the vertical distance between the step 50, and may be may be angled towards the toe end 50-1 of the adjacent lower step 50 so as not to obstruct, or minimize any obstruction, of the user-supporting surface of the lower adjacent step. The individual step shrouds 14-i may be held at such an inclined hanging position, for example by a rope, bungie or other suitable flexible member 17. In some embodiments, the individual step shrouds 14-i may be retractable such as by a roll-up mechanism which operates to roll the sheet of flexible material within a housing (e.g., a cylindrical housing). In other embodiments, the individual step shrouds 14-i may be moved out of the way, if needed, such as when the steps wrap around the guide disks, by a retraction mechanism 16. The retraction mechanism 16 may be configured to retain or automatically pull the lower end of the shroud 14-i towards the underside of the step 50 when the step begins to articulate (e.g., wrap) around a guide disk. The retraction mechanism 16 may include one or more flexible members 17 (e.g., ropes of bungees), attached to the lower end of the shroud 14-i. The one or more flexible members may be anchored to any suitable location on the step 50 (e.g., the toe end 50-1, or looped around a structure at the toe end 50-1 and anchored near the heel end 50-2 of the step) so as to maintain the handing edge of the shroud 14-i at the desired location below the step 50 (e.g., at a desired inclination or handing distance from the underside of the step).

In other embodiments, the riser spaces between adjacent steps may be shrouded by a continuous shroud 14-c. The continuous shroud 14-c may be configured to move with the movement of the steps 50 to substantially conceal between the plurality of steps. As shown in FIG. 15, a continuous shroud 14-c may be implemented using a continuous sheet of flexible material 18, routed around a set of rollers to follow the zig-zagging path shown in FIG. 15. On the front side 11, the sheet of flexible material 18 is routed under and over rear rollers 19-1 and front rollers 19-2, respectively, passing on the underside of each step 50. The sheet of flexible material 18 is routed to the underside 15 of the stepmill and forms a continuous loop of material, which moves in synchrony with the movement of the steps. In other examples, a continuous shroud may be provided, which does not move along the continuous path of the steps.

For example, referring to FIG. 16, a continuous shroud 14-d may be provided in plane behind the rear (or toe) sides 50-1 of the steps 50. The shroud 14-d may be implemented using a sheet of material 8. The material 8 may be rigid, semi-rigid or flexible. The sheet of material 8 may be configured to remain substantially stationary while the steps 50 are traversing their closed loop path. The shroud 14-d may be coupled to an upper support structure 9 (e.g., a bar, roller, or any other suitable structure) located near the top of the four-bar linkage 41, such as near the upper pivot joint between the second and third links. In some embodiments, the upper support structure 9 may be axially aligned with the pivot axis A₄. The shroud 14-d may extend from this location (e.g., from axis A₄) towards the lower side of the four-bar linkage 41, e.g., to a location near the rear lower pivot joint between the second link 44 and the ground link. The shroud 14-d may be positioned forward of the pivot axis A₂ in a manner that does not interfere with the rotation and/or other movement of any of the components (e.g., of the four bar linkage 41 and/or the drive assembly 30). The sheet of material 8 may lie in a plane which is forward of the plane defined by the undersides of the inner and outer loops P_(I) and P_(O). As such, when the steps move to the underside of the closed loop path, they are located behind the sheet of material 8 and thus concealed from the user by the shroud 14-d. The shroud 14-d may include a curved lower portion and/or a curved upper portion which may provide excess material to facilitate the incline adjustments effected by the relative movement of the four-bar linkage 41 relative to the base 21. In some examples, the sheet of material 8 may be sufficiently elastic such that the additional material may be provided through extension of the length of the sheet material 8.

Referring back to FIGS. 1-3, and 5A-5B, the stepmill 10 may include handlebars 27, which can be used by the user to support at least a portion of his or her weight during use of the machine. The handlebar assembly 26 is supported by and extends above the base 21. The handlebar assembly 26 includes a pair of handlebars 27 including a first (e.g., left) handlebar 27 a and a second (e.g., right) handlebar 27 b. Each of the handlebars 27 is supported by a pair of stanchions including a front and rear stanchion 28 and 29, respectively. In other words, the left handlebar 27 a is supported by front and rear left stanchions 28 a and 29 a and the right handlebar 27 b is, similarly, supported by front and rear right stanchions 28 b and 29 b. The handlebars 27 may be implemented by any suitable structure (e.g., a steel, plastic, or composite tube or other rigid member of suitable geometry to facilitate being gripped by a user) that can be used for supporting at least a portion of the user's weight while using the stepmill 10. In some embodiments, the stanchions may extend substantially vertically from the base and may thus be substantially parallel to one another. In some embodiments, one or both of the stanchions of a given pair (e.g., the left or right pair) may be inclined relative to the vertical direction and thus the stanchions in a pair may not be parallel to one another. In some embodiments, one or both of the stanchions of one pair (e.g., the left pair) may be inclined to vertical and may thus not extend parallel to one or both of the stanchions of the other pair (e.g., the left pair). In some cases, one or both of the stanchions of both pairs may be inclined to the vertical direction, such as by having the bases of corresponding stanchions (e.g., the bases of the front stanchions and/or of the rear stanchions) being spaced apart farther than the upper ends of the corresponding stanchions (e.g., the handle-bar ends of the front stanchions and/or the-handle-bar ends of the rear stanchions).

In some embodiments in which the incline of the stepmill is adjustable, the handlebars 27 may be movably (e.g., pivotally) coupled to the stanchions such as to allow for adjustment of the incline of the handlebars corresponding to adjustments to the incline of the frames 40 a and 40 b. For example, the left handlebar 27 a may be pivotally coupled to the upper ends 28 a-2 and 29 a-2 of the front and rear left stanchions 28 a and 29 a, respectively. The right handlebar 27 b may be pivotally coupled to the upper ends 28 b-2 and 29 b-2 of the front and rear right stanchions 28 b and 29 b, respectively. In some embodiments, either the front or the rear stanchions may move relative to the base during adjustments to the incline of the stepmill 10. Referring to FIGS. 17A and 17B, the handlebar assembly 26 may form a secondary four-bar linkage 41′ different from the primary four-bar linkages 41 formed by the respective sides of the upright frame 40. The secondary four-bar linkage 41′ (e.g., the handlebar assembly 26) may be operatively coupled to the primary four-bar linkage 41 (e.g., the upright frame 40) such that movement of the primary four-bar linkage 41 (e.g., the upright frame 40) causes the secondary four-bar linkage 41′ to move to adjust the position of the handlebars 27 (e.g., to position them suitably for use at a different incline angle). The secondary four-bar linkage 41′ includes a fixed link 48′ which may be defined by the front stanchions 28. In such embodiments, the front stanchions 28 may be fixedly coupled to the base 21, for example at a location along the length of the fixed link 48 of the primary four-bar linkage 41. The fixed link 48′ of the secondary four-bar linkage 41 may extend substantially perpendicularly (e.g., vertically upward) from the fixed link 48 of the primary four-bar linkage 41. A first moving link 42′ may be pivotally coupled, at one end, to the fixed link 48′ and pivotally coupled, at its opposite end, to the third moving link 46′. The first moving link 42′ may be defined by the respective one of the left and right handlebars 27. The third moving link 46′, which may be defined by the rear stanchions 29, may be coupled (e.g., rigidly), at its opposite end, to the third link 46 of the primary four-bar linkage 41. For example, the third link 46′ may be coupled at a location along the length of the third link 46. Since the third link 46 of the primary four-bar linkage 41 is movable relative to the fixed link 48, the third moving link 46′ is movable relative to the fixed link 48 of the primary four-bar linkage 41 as well as the fixed link 46′ of the secondary four-bar linkage 41. A second moving link 44′ is defined by the coupling location 48-1 of the secondary fixed link 48′ to the primary fixed link 48 and the coupling location 46-3 of the secondary third link 46′ to the primary third link 46. The second moving link 44′ may be a virtual link or, in some cases, may be optionally provided by a rigid member extending between the coupling locations 48-1 and 46-3.

As shown also in FIG. 17B, which illustrates the stepmill in a different incline position from the positioned shown in FIG. 17A, as the primary four-bar linkage 41 is lowered towards the base 21, which corresponds to a decrease in the incline angle of the stepmill, the secondary four-bar linkage 41′ automatically moves, through its connection to the primary four-bar linkage 41 to adjust, in this example reduce, the incline angle of the handlebars 27 to correspond to the incline angle of the stepmill 10. In this example, because the secondary four-bar linkage 41′ is shaped as a parallelogram, whereby the opposing links are parallel to one another, the incline angle of the handlebars 27 corresponds to the incline angle of the second moving link 44′, which is the incline angle of the stepmill 10. In other embodiments, one or both of the primary and secondary four-bar linkages may have a quadrilateral geometry other than a parallelogram. For example, the secondary four-bar linkage may generally define a trapezoid, with the handlebars extending along the shorter side of the trapezoid, as shown in FIG. 24. In some embodiments, additionally or alternatively, a component other than the front stanchions may define the fixed link of the secondary four-bar linkage. For example, the fixed link may be the link (physical or virtual) that extends between the front and rear stanchions. Other suitable arrangements may be used in other examples.

The stepmill 10 may optionally include a transverse handlebar 25 which may be located near the rear end of the handlebars 27. The transverse handlebar 25 may be used by a user for supporting at least a portion of his or her weight. The transverse handlebar 25 may be discontinuous, for example including a right side portion and a left side portion, that extend transversely but span only along part of the right and left halves, respectively, of the machine. Other suitable combinations may be used. In some examples, the transverse handlebar 25 may remain stationary to the base 21 (e.g., during adjustments of the incline of the stepmill) and may also, optionally, be used for mounting or stabilizing other components of the machine (e.g., a console) such that they may remain stationary during incline adjustments. The location of the transverse handlebar 25 between the front and rear sides of the machine may be selected so as to prevent or guide the user to remain within an optimal exercise space of the machine (e.g., to prevent or guide the user from stepping too far forward and/or prematurely forward on the top step before it has completely unfolded after traversing over the top guide disk(s)).

The movement of components of the drive assembly 30, such as responsive to user force (e.g., the user's foot pressing a step 50 downward) may be resisted by a resistance mechanism 90. The resistance mechanism 90 may be operatively coupled to one or both of the left and right drive sub-assemblies 30 a and 30 b. The resistance mechanism may include any one or a combination of suitable resistance mechanisms that can apply resistance to rotation of a shaft. For example, the resistance mechanism may include a brake (e.g., a friction brake or a magnetic resistance brake, such as an eddy current brake) that resists the rotation of a shaft, which is operatively coupled to the rotation of any one or a plurality of the guide disks (e.g., inner and outer guide disks 34 and 32). In some embodiments, the resistance mechanism may include an air brake, or any combination of a friction based, magnetic-resistance based, or air-resistance based brake.

Referring, for example, to FIGS. 5 and 7, the drive assembly 30 (e.g., the right drive sub-assembly 30 b) may be coupled to a resistance mechanism 90 which includes a brake disk 98. The rotation of the brake disk 98 is resisted via a brake 97 (e.g., a friction brake or a magnetic brake). The rotation of the brake disk 98 and rotation of the right drive sub-assembly 30 b are coupled via any suitable transmission mechanism 91. For example, a transmission disk 92 may be fixed to the rotating shaft of one of the guide disks, here to the common rotating shaft 35-4 of the upper rear disks 32-4 and 34-4, to rotate synchronously with the guide disks. The rotation of the transmission disk 92, which is effectively the rotation of the guide disks, is transmitted to the brake disk 98 via any suitable transmission member 94 (e.g., a flexible member such as a chain or a belt) whereby resistance is applied to the rotation of the brake disk 98, and thus to the rotation of the transmission disk 92 and guide disks, via the brake 97. Other suitable arrangements may be used, for example using a different type of transmission mechanism 91 and/or using multiple-stages of transmission such as to apply a desired gearing ratio between the rotation of the guide disk shaft(s) and the rotation of the brake disk 98.

The rotation of the rotatable components of the drive assembly may be transmitted to the resistance mechanism using any suitable transmission assembly (e.g., gears, chains and sprockets, a belt drive, etc.). In some embodiments, the transmission may be geared so as to provide a gear increase or reduction. One or a multi-stage transmission assembly may be used. For example, a two-stage transmission assembly which provides a speed increase ratio, for example 10:1, 11:1 or greater, 16:1 or other gearing, may be used. Increasing the rotational speed of the shaft to which the resistance is applied may facilitate reducing the size of the resistance mechanism (e.g., a smaller caliper for the friction or eddy current brake), for a more compact overall design. In some embodiments, no gearing may be used and the rotation at the output of the drive assembly may be synchronous with the rotation of the shaft which is resisted by the resistance mechanism.

In some embodiments, a lower step-on height for a stepmill may be achieved using a multi-piece step according to any embodiment of the present disclosure, independent of whether the stepmill is incline-adjustable or not. Referring to FIGS. 19 and 20, a fixed incline stepmill may provide a low step-on height by using a mufti-piece step, each of the pieces of which may be articulated (or wrapped) around the lower guide disk(s), thus reducing the distance or clearance between the lower guide disk(s) and the ground for routing the steps to the rear side (or underside) of the path. While some or all of the frame components have been hidden away in FIGS. 19 and 20 for simplicity and so as to not obfuscate the drive assembly and articulating steps, the stepmill 300 may include a frame having a base according to any of the examples herein such as the base 21 of stepmill 10. The base of the stepmill 300 may be implemented using any suitable structure that can stably support the stepmill 300 on a support surface. The base of stepmill 300 may support an upright frame, which may similarly include a left and right frame portion such that the steps 350 may be movably suspended between the two side frame portions so as not to interfere with the movement of the steps 350. In this embodiment, the upright frame may be substantially fixed, such as to remain in a fixed position, relative to the base of the stepmill 300. For example, the upright frame may be implemented using any suitable combination of rigid members that may be fixedly coupled (e.g., rigidly connected or integrally formed) to the base of the stepmill 300. The stepmill 300 may include a drive assembly 330 which movably couples the plurality of steps 350 to the frame 320.

Each of the steps includes an articulating step platform 352 formed of a plurality (e.g., two or more) slats 353. Adjacent slats 353 of the plurality of slats that form each step platform are pivotally connected to one another, e.g., via a hinge 359 or other suitable pivot joint, to allow the step platform 352 to articulate (e.g., curve or wrap around the guide disk(s) 332, 334) as each step 350 moves from the front (or user-facing) side 311 of the closed loop path 338 to the rear side (or underside) 315 the closed loop path 338 or vice versa.

The drive assembly 330, on each of the left and right sides of the stepmill 300, may include one or more upper disks 332 and one or more lower disks 334, each of which may be implemented using any suitable combination of sprockets, rollers, pulleys, drums, or other rotatable elements, that guide the movement of the steps 350. A flexible member 336, such as a chain, belt, rope, cable, or other, may be wrapped, in a continuous loop, around the set of disks located on each of the left and right sides of the stepmill 300, to define the closed loop path 338 traversed by the steps 350. In some embodiments, the size (e.g., diameter) of the one or more lower disks 334 may be smaller than a corresponding size (e.g., diameter) of the upper disk(s) 332, for example up to about ½ of the size of the upper disk(s) 332. The size (e.g., diameter of the lower and/or upper disks 334 and 332, respectively, may be selected based on the width W_(S) of the individual slats 353. In some embodiments, the size (e.g., diameter) of one or more of the disks 334 and 332 may be about the same as the width W_(S) of the slats. In other embodiments, the size of the disks may be differently selected. For example, the diameter of the lower disks 334 and/or the upper disk(s) 332 may be selected to ensure that the slats 353 do not cross the rotation axis of the respective disk.

In some embodiments, one or more of the disks 332 or 334 may be driven by a power source (e.g., a motor) to cause the steps to move in the closed loop path without the application of force from the user. In such embodiments, the speed of rotation of the disks 332 and 334, and consequently the speed of downward movement of the steps 350, may be selectively adjusted by controlling the operation of the power source (e.g., the rotational speed of a motor). In some embodiments, the disks 332 and 334 may rotate solely responsive to the application of force by the user (e.g., resulting from the user placing at least some of his or her weight on one or more of the steps 350) and/or due to gravity. In some such embodiments, the movement of the disks 332 and 334 or flexible member 336, and consequently of the steps 350, may be resisted by a resistance mechanism, which may reduce the amount of exertion by the user, and thus the intensity of the exercise.

Each step 350 may be coupled to fixed location along the length of the flexible member 336. The steps 350 may be evenly spaced apart along the continuous loop formed by the flexible member. The spacing between the steps 350 may be selected to ensure that adjacent steps 350 do not interfere (e.g., overlap or otherwise come into contact) with one another whether traversing on the front or rear sides of the closed loop path 338. The left and right sides of each step 350 may be coupled to the flexible member 336 using any suitable mounting arrangement that fixes the location of the step 350 along the length of the flexible member 336. For example, each step 350 may be provided, on each of its left and right sides, with a first (e.g., front) mount 354-1 and a second (e.g., rear) mount 354-2 such that the step is joined to the flexible member at two locations along the depth D of the step 350. In some embodiments, the front and rear mounts may be located at or near the toe end and heel end, respectively, of the step other embodiments, the mounts 354-1 and 354-2 may be located elsewhere. For example, in some embodiments of a two-slat step 350, as shown in FIGS. 20A and 20B, the first mount 354-1 may be generally centrally located along the width W_(S) of the first (e.g., toe-end) slat 353-1 and the second mount 354-2 may be generally centrally located along the width W_(S) of the second (e.g., heel-end) slat 353-1. The first mount 354-1 may include a first rigid link 356-1 extending in one direction with respect to the user-supporting surface 351 of the step 350 and the second mount 354-2 may include a rigid link 356-2 extending in a different (e.g., the opposite) direction than the first link 356-1, which may enable attaching the step 350 to the same flexible member 356. In some embodiments, the second rigid link 356-2 may extend upward (e.g., away from the user-supporting surface 351 of the step 350) and the first rigid link 356-1 may extend downward (e.g., away from the underside of the step 350). In some embodiments, the links 356-1 and 356-2 may extend in diametrically opposite directions when the step is in the flat configuration, for example the links 356-1 and 356-2 may be substantially perpendicular to the user-supporting surface 351. A pin 357 may extend laterally away from each of the links toward the flexible member 336 and be joined thereto such as to couple each step 350 to the flexible members 326. In some embodiments, each step 350 may be connected to the respective (e.g., left or right) flexible member using at least one pin 357 located above and at least one additional pin 357 located below the user-supporting surface 361 of the step 350.

The relative movement between adjacent slats 353 of a step 350 may be limited, for example to allow the slat 353 to rotate in one direction, bringing the undersides closer, but not in the opposite direction. The slats may be so limited using any suitable mechanism, for example a tension member (e.g., 271 as in the example in FIGS. 14A and 14B) that extends along or near the lower side of the step. Additionally or alternatively, rotation or over rotation in the undesired direction may be reduced or limited by mounting the pivot axis 359 to the flexible member 336, which effectively and substantially constrains the movement of that location on the step to the closed loop path 338.

In some cases, it may be desirable to use a monolithic (also referred to as a unitary, single-piece, or fixed) step platform, while still achieving a lower step-on height H_(SO) (e.g., a step-on height of up to 12 inches) and, optionally, incline-adjustability. For example, a lower step-on height, when using a fixed step, may be achieved with a drive assembly or system that, instead of wrapping each step around guide disks, flips the steps under and/or over the guide disks. Optionally, such a stepmill may also be incline-adjustable, which can be achieved, e.g., by supporting components of the drive system on left and right upright frame portions that form respective left and right four-bar linkages.

FIG. 20 shows a simplified illustration of step routing for a stepmill that has fixed (or single-piece) steps. The steps 2150 may be operatively coupled to the frame of the stepmill by a drive system 2110 to move along a closed loop path and such that each step 2150, when traversing the front side 2111 of the closed loop path, is positioned substantially horizontally and can support one or both of the user's feet. The drive system 2110 operatively couples and routes, along the closed loop path, both the toe ends 2151 and the heel ends 2153 of each step 2150. The toe ends 2151 of the steps 2150 may be constrained to move along a first closed loop path 2138 and the heel ends 2153 of the steps 2150 may be constrained to move along a second closed loop path 2139, which collectively define the overall closed loop path traversed by the steps 2150. Each of the first and second closed loop paths 2138 and 2139 may be defined by any suitable combination of components (e.g., flexible members routed around guide disks, tracks, or other mechanisms, or combinations thereof) that can constrained the toe ends 2151 and the heel ends 2153, respectively, of each step 2150 to move along the desired path. For example, the first closed loop path 2138 may be defined by a flexible member 2136 (e.g., a cable, belt, chain, etc.) which is routed, in a continuous loop, around at least one lower disk 2134 and at least one upper disk 2132. The toe ends 2151 of each step 2150 may be constrained to travel along the first closed loop path 2138, such as by being attached at predetermined (or fixed) positions along the continuous loop formed by flexible member 2136. As such, the shape of the continuous loop formed by the flexible member 2136 corresponds to the closed loop path 2138 traversed by the toe ends 2151 of the steps 2150.

The heel ends 2153 of each step 2150 may be constrained to travel along a second closed loop path 2139. The second closed loop path 2139 may be defined in part by a track system 2120 that extends along at least a portion of the closed loop path 2139. A remaining portion of the second closed loop path 2139 may be defined by wheel 2142. The wheel 2142 may be arranged coaxially with the upper disc 2132 so as to rotate in synchrony with and about the same rotation axis as the upper disk 2132. The wheel 2142 may include a plurality of engagement (or pick-up) features 2143 operable to, at least temporarily, support each step in a predetermined position with respect to the wheel. The pick-up features 2143 may be provided at different radial positions, for example regularly spaced along the periphery of the wheel 2142. A pick-up feature 2143 may be implemented as ledge extending from the surface of the wheel 2142 such that the ledge is positioned against the underside of a step 2150 as each step 2150 is moved into a position overlapping the wheel 2142.

The track system 2120 includes a first (e.g., front side) portion 2120-1, a second (e.g., rear side) portion 2120-2, and a third (e.g., lower transition) portion 2120-3, which in combination span the front and rear sides of the closed loop path 2139 and the lower curved portion of the closed loop path 2139. The heel ends 2153 of the steps 250 are provided into the first portion 2120-1 of the track system 2120 via a track entrance 2122. The heel ends 2153 of the steps 2150 traverse the path defined by the track system 2120 until they reach the track exit 2124 located at the rear side (or underside) 2115 of the closed loop path 2139, whereupon the heel end 2153 of each step 2150, as it exits the track system 2120, is picked up by the wheel 2142 and guided around the rotation axis of the upper disk 2132 until the heel end 2153 of the step 2150 reaches the track entrance 2122 and is again provided thereto. The heel ends 2153 of the steps 2150 may engage the track system 2120 using any suitable combination of sliding and/or rolling components, such as one or more wheels (or rollers) located at the opposite (left and right) heel ends 2153 of each step. As such, the heel end 2153 of each step 2150 may be in rolling engagement with a part of the track system 2120 (e.g., a first and/or second track member 2121-1 and 2121-2, respectively) when the heel end 2153 is traversing the portion of the closed loop path defined by the track system 2120. In some embodiments, one portion of the track system, such as the first (or front) portion 2120-1, may be defined by a plurality of track members (e.g., first and second track members 2121-1 and 2121-2 respectively), while other portion (e.g., the second portion 2120-2 may be defined by only one track member. In embodiments, any of the portions of the track system may be defined by a single track member.

As shown in FIG. 20, each step 2150 is flipped under the lower disk 2134 such that the user-supporting side 2154 of each step 2150 remains facing generally towards the user when the step 2150 is traversing the underside 2115 of the closed loop path 2139. The drive system 2110 is configured to flip each step 2150 when the step 2150 is routed from the front (or user-facing) side 2111 to the rear side (or underside) 2115 of the closed loop path 2139 such that the user-supporting surface of the step 2150 remain facing generally toward the front of the stepmill, while the step 2150 is traversing the underside of the path. To do so, the drive system 2110 is configured to move the toe end 2151 from a trailing position to a leading position when the step moves from the front side to the underside 2115 of the closed loop path 2139. Conversely, the heel end 2153 changes form a leading to a trailing position when the step transitions from the front side 2111 to the underside 2115 of the closed loop path 2139. The terms trailing and leading positions imply relative position with respect to a location along the closed loop path 2139. For example, as can be seen in FIG. 20, at an exemplary position X₁ along the loop path 2139, and taking into consideration the direction of travel of the steps, the heel end 2153 of step 2150 is in a leading position relative to (or ahead of) the toe end 2151 of the same step 2150, which is some distance behind the heel end 2153, as indicated by the dashed lines drawn for illustration only, normal to the path 2139. In contrast, at position X₂ along the loop path 2139, the heel end 2153 of step 2150 is in a trailing position relative to (or behind, considering the direction of travel) the toe end 2151 of the same step 2150, which is some distance ahead the heel end 2153. As each step 2150 moves around the lower disk 2134, the position of the heel end 2153, relative to the toe end 2151, changes from a leading position to a trailing position.

On the upper side of the closed loop path 2139, when returning the step 2150 from the rear side 2115 to the front side 2111 of the path 2139, the steps 2150 may be rotated about the axis A_(D) of the upper disk 2132 (as shown in FIG. 20), for example using a wheel 2142 with step engagement features 2143. Each step 2160 is rotated, at the upper side of the closed loop path 2139, in the same direction (e.g., counter-clockwise when referring to the view shown in FIG. 20) as the direction in which the upper disk 2132 rotates. That is the steps 2150 are rotated in the direction of travel of the steps, as indicated by arrow 2159. The wheel 2142 may have a larger diameter than the diameter of the upper disk 2132 allowing the end of the step that is trailing, here file heel end 2153, to catch up with and take up a leading position when deposited into the track entrance 2122. In other embodiments, each step may again be flipped relative to, rather than rotated about, the upper disk(s) e.g., as shown in FIG. 21). Such a configuration may provide a more compact design, by removing the structure (e.g., the pick-up wheel 2142) that supports the heel ends 2153 of the step 2150 as they are rotated about the upper disk 2132. Any suitable mechanism may be used on the upper side of the path 2139 to flip the steps 2150 and thereby re-position the heel ends 2153 from a trailing position to a leading position as the steps 2150 transition from the rear side 2115 to the front side 2111 of the path 2139. An example of such a mechanism, which may also be referred to as a step flipper, is shown in FIGS. 21 and 22A-22C.

FIG. 21 shows another simplified illustration of step routing for a stepmill that has fixed (or single-piece) steps. The steps 2250 are movably coupled to the frame 2201 of a stepmill via a drive system 2210, which substantially constrains the movement of the steps 2250 along a closed loop path. When travelling along the front side 2211, each step 2250 is positioned substantially horizontally and can support one or both of the user's. The steps are spaced apart and parallel to one another to define a step height S_(H), which may be defined as the vertical distance between the user-supporting sides 2254 of adjacent steps 2250 when located on the front side 2211 of the stepmill, and which may be adjustable (e.g., by the user). When traversing, the rear side of the closed loop path, the steps 2250 may be substantially in-plane with one another.

The drive system 2210 operatively couples and routes the toe ends 2251 and the heel ends 2253 of each step 2250 along respective closed loop paths, to define the overall closed loop path of the steps 2250. The toe ends 2251 of the steps 2250 may be constrained to move along the first closed loop path 2238 and the heel ends 2253 of the steps 2250 may be constrained to move along a second closed loop path 2239. Each of the first and second closed loop paths 2238 and 2239, respectively, may be defined by any suitable combination of components (e.g., flexible members routed around guide disks, tracks, or other mechanisms, or combinations thereof) that can constrain the movement of the steps along a desired path. For example, the first closed loop path 2238 may be defined by a flexible member 2236 (e.g., a cable, belt, chain, etc.) which is wrapped in a continuous loop, around at least one lower disk 2234 and at least one upper disk 2232. The toe ends 2251 of each step 2250 may be constrained to travel along the first closed loop path 2238, such as by being attached at predetermined (or fixed) positions along the continuous loop formed by flexible member 2236. As such, the shape of the continuous loop formed by the flexible member 2236 corresponds to the closed loop path 2238 traversed by the toe ends 2251 of the steps 2250. In some embodiments, the steps 2250 may engage additional guide elements (e.g., additional flexible members and/or tracks) to facilitate the routing of the steps 2250 along their closed loop path.

Similar to the drive system 2110, the drive system 2210 is configured to flip each step 2250 under the lower guide disk 2234. The configuration and operation of the drive system 2210 may be substantially the same as that of drive system 2110 along the front, rear and lower transition sides of the steps' closed loop path. The steps 2250 may be coupled to the drive system 2210 such that their toe ends 2251 and heel ends 2253 are constrained to move along respective paths 2238 and 2239. Like in the example in FIG. 20, the toe ends 2251 are coupled to a flexible member 2236, which is arranged in a continuous closed loop around upper and lower disks 2232 and 2234, respectively, and thereby the toe ends 2251 traverse a closed bop path 2238 corresponding to the continuous loop formed by flexible member 2236. The toe ends 2251 may be pivotally coupled to the flexible member 2236, to enable the orientation of the steps 2250 with respect to flexible member 2236 to vary as the steps traverse their closed loop path. The toe ends 2251 are coupled at fixed locations along the continuous loop formed by flexible member 2236 such that their relative spacing S_(S) remains fixed. The relative spacing S_(S) may be selected to avoid interference (e.g., contact) between adjacent steps whenever the steps are oriented along or aligned with the path 2238 or 2239, for example when the steps are traversing the underside 2215 of the path 2238 and/or when the stepmill is adjusted to a substantially zero-incline position.

The heel ends 2253 of the steps 2250 are substantially constrained to move along the closed loop path, a portion of which is defined by a track system 2220. The track system 2220 may be configured similarly to the track system 2120. The track system 2220 may include a first (e.g., front side) portion 2220-1, a second (e.g., rear side) portion 2220-2, and a third (e.g., lower transition) portion 2220-3, which in combination span the front and rear sides 2211 and 2215, respectively, as well as the lower curved portion, of the closed loop path 2239. The heel ends 2253 of the steps 2250 are provided into the first portion 2220-1 of the track system 2220 via a track entrance 2222. The heel ends 2153 of the steps 2150 traverse the path defined by the track system 2220 until they reach the track exit 2224 located at the rear side (or underside) 2215 of the closed loop path 2239, whereupon a step flipper 2260 engaged each step 2250 as it is exiting the track system 2220 and rotates the step 2250 in a direction, indicated by arrow 2257, which is opposite the direction of rotation of the disks 2232 and 2234, indicated by arrows 2259, and thus opposite the direction of travel of the toe ends 2251 of the steps 2250. The heel ends 2253 may be configured for operative (e.g., rolling) engagement with the one or more track members (e.g., a first track member 2221-1 and/or a second track member 2221-2) of the track system 2220.

As such, the drive system 2210 is configured to flip each step 2250 twice in each closed loop traversed by a step. At the lower end of the path 2239, each step 2250 is flipped to reverse the relative position of the toe end 2251 with respect to the heel end 2253 from a leading to a trailing position. At the upper end of the path 2239, each step 2250 is again flipped to reverse the relative position of the toe end 2261 with respect to the heel end 2263 from a trailing position to a leading position.

A step flipper 2260 may be implemented using any suitable structure which can engage a portion of the step 2250, for example the toe end 2251 of the step 2250, to re-orient and/or reposition the heel end 2253 of the step 2250 as the toe end 2251 continues along its closed loop path. For example, the step flipper 2260 may include one or more rigid members 2262 (e.g., bar, rod, plate, etc.) positioned near the upper disk 2232. The rigid member 2262 is positioned with its first end 2262-1 outside of the closed loop path defined by the flexible member 2236 and with its second end 2262-2 positioned so as to align the member 2262 with the direction of travel along the rear side of the closed loop path. The rigid member 2262 may thus be operatively positioned to engage the toe end 2251 of the step, as shown in FIG. 22A, as the toe end 2251 is pulled along the closed loop path by flexible member 2236. The first end 2262-1 of the rigid member 2262 is pivotally coupled to the frame. The second send 2262-2, which is the free end of the rigid member 2262, is received within the step 2250 as shown in FIG. 22A, or otherwise operatively engages for example to an underside of the step 2250. As the step 2250 is pulled further along the closed loop path, for example through the connection between the toe end 2251 to the flexible member 2236, the engagement of the rigid member 2262 with the step 2250 causes the step platform to rotate or pivot about the pivot axis of the first end 2262-1 of the rigid member 2262, as shown in FIG. 22B, whereby the heel end 2253 of the step 2250 is lifted off the lower track to be repositioned onto the upper track, as shown in FIG. 22C. As the step 2250 continues along the closed loop path, e.g., responsive to being pulled along the first closed loop via the connection between the toe end 2251 and the flexible member 2236, the step 2250 disengages from the rigid member 2262 by moving away from, allowing the rigid member 2262 to withdraw from the step 2250. The length of the rigid member 2262 may be selected to ensure that the rigid member 2262 disengages from (e.g., so as to no longer be inserted into or otherwise supporting) the step 2250 upon engagement of the heel end 2253 of the step with the upper track.

A drive system configured to flip the steps, such as the drive system 2110 or the drive system 2210, may be operatively supported on a moving frame (e.g., first and second four bar linkages 41), to enable selectively varying the incline of the moving frame, thereby selectively changing the vertical distance between the steps (e.g., steps 2150 or 2250). For example, the upper and lower disks 2232 and 2234, respectively, may be rotatably coupled to opposite ends of the first link 42 of the four-bar linkage 41, for example coaxially with the pivot axes A₂ and A₄ associated with the first link 42. The track system 2220 may be operatively supported by the four-bar linkage 41 to enable the incline adjustments to the stepmill. For example, the first and second portions 2220-1 and 2220-2 of the track system may run parallel to the first and second links, which are also parallel to one another. The first and second portions 2220-1 and 2220-2 of the track system 2220 may move with the first and second links to remain parallel thereto when the first and second links are repositioned relative to the base 21.

In some embodiments, the drive system may include a second lower disk 2235, which supports the heel end 2253 of a step 2250 as the toe end 2251 of the step 2250 is flipped around and under the lower disk 2234 via its connection to the flexible member 2236. Referring also to FIG. 23, which shows an enlarged view of the lower portion of the drive system, the second lower disk 2235 is positioned forward of the lower disk 2234 such that its rotation axis is parallel to the rotation axis of the lower disk 2234. In some embodiments, the second lower disk 2235 may be coaxial with, and thus rotate about, the pivot axis A₁, which is the pivot axis between the first link 42 and the ground link 48 of the four-bar linkage 41. The second lower disk 2235 may rotate independently of any movement (e.g., pivotal movement about axis A₁) of the second link 42 relative to the ground link 48. The second lower disk 2235 may rotate in the same direction 2 as the direction of rotation 2205 of the lower disk 2234, and in some embodiments, synchronously therewith, which may be achieved by coupling the shaft of the two disks by a suitable flexible member 531 (see FIG. 34), which may be a chain, a belt or other flexible member.

The second lower disk 2235 includes radial engagement features (e.g., radial recesses) 2237 operatively spaced about the circumference of the second lower disk 2235 to engage (e.g., receive, in the case of a recess) the heel end 2253 of each step 2250 as the step 2250 reaches its lowest vertical supportive position. The term supportive position refers to a position in which the step a oriented to support a user's foot. In other words, a supportive position is a position which the step is substantially horizontally oriented. The second lower disk 2235 may thus engage and/or support the heel end 2253 of the step 2250 while the toe end 2251 is rotated around the lower disk 2234, flipping the step 2250 under the lower disk 2234. In operation, as the lower disk 2234 rotates, pulling the toe end 2251 around the lower curve of the closed loop path 2238, the second lower disk 2235 rotates, maintaining the heel end 2253 of the step 2250 forward of the lower disk 2234, until the toe end 2251 has rounded the lower disk 2234 and begins advancing along the underside of the closed loop path, thereby facilitating the reversal of the leading and trailing positions of the heel and toe ends. In some embodiments, the second lower disk 2235 may be synchronized with the lower disk 2234. For example, the lower disks 2234 and 2235 may be operatively connected by a transmission member 2241 which is shown here as a flexible member (e.g., a belt, chain, cable, etc.), but may instead be one or more gears or any other suitable combination of elements that can transmit the rotation of the disk 2234 to the rotation of the disk 2235 or vice versa.

FIGS. 24-34 show views of a stepmill 600 and components thereof. In FIGS. 24-34 one or more component of the stepmill 600, such as one or more of the steps, may be removed in a particular view so as not to obfuscate other components and facilitate the description and understanding thereof. The stepmill 600 includes a frame 620, which movably supports a plurality of monolithic (one-piece) steps 650. The stepmill 600 provides a low step-on height H_(SO), measured from the ground to the lowest position of a step 650 in which the step is oriented to support the user's foot. In some embodiments, the stepmill 600 is configured to provide a step-on height H_(SO) that does not exceed approximately 12 inches. The stepmill 600 has a drive assembly 630 which is configured to flip each step 650 twice in a single loop of the closed loop path. Each step 650 is flipped at the transition from the front side 611 to the rear side 615 of the path and is again flipped at the transition from the rear side 615 to the front side 611 of the path. In flipping the steps 650 in this manner, the steps 650 remain with their user-supporting side oriented towards the front (or user) side 611 of the stepmill throughout substantially the entire closed loop path. The stepmill 600 may, optionally, be incline-adjustable, allowing the step-height H_(S), which is the vertical distance between adjacent steps when located on the user-facing side 611 of their closed loop path, to be adjusted, for example by the user while the user using the stepmill 600 to perform exercise.

The frame 620 includes a base 621 for supporting the stepmill 600 on a surface (e.g., the ground). The frame 620 also includes an upright frame 640 coupled to the base 621. In some embodiments, the upright frame 640 may be movably coupled to the base 621 for selectively adjusting the incline of the stepmill 600. The base 621 may be implemented using any suitable combination of structures that can stably support the components of the stepmill 1600. For example, the base 621 may include one or more first beams 622, which may extend substantially lengthwise between the front and rear sides 611 and 615 of the stepmill 600, and one or more cross-beams 624 operatively coupled to (e.g., transversely extending and/or connecting) the one or more first beams 622 to provide a stable support structure for the stepmill 600. The upright frame 640 may be movably coupled to the base 621 to allow the incline angle of the stepmill 600, and consequently the step-height H_(S), to be selectively adjusted. The upright frame 640 may include a left frame portion 640 a and a right frame portion 640 b spaced apart from one another to define a central space 603 that accommodates the steps 650 there between. In some embodiments, the left and right frame portions 640 a and 640 b, respectively, may be connected, such as by one or more cross-members 643 extending across the central space 603 (e.g., behind the steps 350 or elsewhere positioned so as not to interfere with the movement of the steps 650). The cross-member(s) 643 may tie the left frame portion 640 a and the right frame portion 640 b such that the two move together relative to the base 621, e.g., when the incline of the stepmill 600 is being adjusted.

A lift mechanism 880 may apply a force to the upright frame 640 to move the upright frame 640 relative to the base 621. The upright frame 640 may thus also be referred to as the moving portion of the frame, or simply moving tame 640. The lift mechanism 660 may be operated in one direction to raise the moving frame 640, thereby increasing the incline angle of the stepmill 600, and a second opposite direction to lower the moving frame, thereby decreasing the incline angle of the stepmill 600. In some embodiments, the incline angle of the stepmill 600 may be selectively adjustable from a minimum incline angle, e.g., a substantially zero incline, which is a position in which the moving frame 640 is substantially horizontal and the vertical distance between the steps (i.e., the step height S_(H)) is substantially zero, up to a maximum incline angle, for example an incline of about 55 degrees from horizontal, or more. In some embodiments, the maximum incline angle may be up to about 50 degrees or up to 45 degrees. In some embodiments, the stepmill 600 may be adjustable up to a 60 degree incline. The incline may be adjustable to virtually any incline angle between the minimum and maximum incline. In other embodiments, the incline may be adjustable in predetermined increments, such as in 5 degree increments, 2 degree increments, 1 degree increments or other. One or more lift mechanisms 660 may be used for raising or lowering the moving frame 640. In some embodiments, a single lift mechanism 860 may apply, a force, for example to one of the left or right frame portions 640 a and 640 b or to the cross-member 643. In some embodiments, separate lift mechanism may apply a force to each of the respective sides of the upright frame 640. In some such embodiments, the plurality of lift mechanisms 860 may be timed or otherwise synchronized to move the two sides of the upright frame 640 together.

The plurality of steps 650 are movably coupled to the frame 610 such that they traverse a closed loop path. In some embodiments, the steps 650 are caused to move along their closed loop path, by constraining the movement of at least two locations along the depth (e.g., the toe end and the heel end) of each step. The toe ends 651 of the step 650 may be substantially constrained to traverse a first closed loop path and the heel ends 653 of the steps 650 may traverse a second closed loop path, which, in some embodiments, may have a different shape than the first closed loop path. The first and second closed loop paths of the toe ends and heel ends, respectively, may together define the overall closed loop path traversed by each step (e.g., the closed loop path of a central location of the step like the center of gravity or geometric center of the step).

The steps 650 may be movably coupled to the frame by a drive system 630. The drive system 630 operatively couples the movement of one step 650 to that of the remaining steps 650 such that when a force applied to one step 650, e.g., a downward force applied by a user's foot, all of the steps 650 move in a synchronized manner along the closed loop path. The drive system 630 is configured to flip each of the steps 650 at the transition from the front (or user-facing) side 611 to the rear side 615 of the stepmill 650, whereby the steps 650 remain oriented substantially toward the user-facing side of the machine while traversing the rear side of the closed loop path. The drive system 630 is further configured to flip each of the steps 650 at the transition from the rear side 615 to the front side 611 of the stepmill 650 to position each step 650 in a position suitable to support the user's foot (e.g., a substantially horizontal position) as each step 650 advances toward the front side 611 of the stepmill 600.

The toe ends 651 of the steps are constrained, by the drive system 630, to follow a first closed loop path, and the heel ends 653 of the steps are constrained, by the drive system 630 to follow a second closed loop path. The first closed loop path may be defined by a flexible member (e.g., a chain, belt, cable, or other) wrapped around a pair of spaced apart rotating members (e.g., a sprocket, drum, wheel, roller, or other type of rotatable member configured to engage through interlocking anion friction with the flexible member). The second loop path may be defined, at least in part by a track system

Focusing now on FIGS. 27-31, the components and operation of the drive system 630 will be described with reference to a first lateral (e.g., right) side of the stepmill 600, noting that the operation and components of the drive system 630 on the second lateral (e.g., left) side of the stepmill 600 are substantially the same.

Each step 650 is operatively engaged with (e.g., mounted to or supported on) the drive system 630 at three support locations on each of its left and right sides, not all of which support a given step at all times along the steps' closed loop path. At any given time along the steps' closed loop path, each step 650 is supported on the drive system by at least two support locations. Referring specifically to FIGS. 29A and 29B, which show views of an example step 650, a support structure 656-1, also referred to as toe support 656-1, is provided at a first location along the depth D of the step 650 for coupling the toe end 651 of the step 650 to the drive system 630. A second support structure 656-2, also referred to as heel support 656-2, is provided at a second location along the depth D to couple or operatively engage the heel end 653 of the step 650 to the drive system 630. A third support structure 656-3 is provided at a third intermediate location along the depth D (i.e. between the first and second locations). The third support structure 656-3 may be used for coupling or operatively engaging an intermediate location of the step 656 between the toe end 651 and heel and 653 with the drive system 630. At least one of the support structures (e.g., the first support 656-1) may support the step 650 continuously as the step 650 traverses its closed loop path. In other words, that support of the step 650 engages with (e.g., coupling the step 650 to) the drive system 630 through its entire closed loop path. At least one of the support structures (e.g., the second and/or third supports 656-2 and 656-3) may only support the step 650 intermittently during the traversal of the closed loop path. In some embodiments, the engagement of a step 650 with the drive system 630 may switch from one support structure (e.g., the second support 656-2) to another support structure (e.g., third support 656-3) and vice versa as the step 650 traverses its closed loop path. In such embodiments, at times when a step 650 is not supported on the drive system by a given support structure, that support structure may be disengaged (e.g. not in contact with and thereby said to be floating) with respect to the drive system 630. As such, the function of supporting or engaging a step 650 with the drive system 630 may pass from one support of the step 650 to another intermittently throughout the traversal of the closed loop path.

In some embodiments, the toe end 651 of each step 650 is mounted to a flexible member 636 (e.g., a chain, belt, cable, rope, etc.), which is wrapped around a set of disks (e.g., sprockets, drums, rollers, pulleys, or the like depending on the choice of flexible member) that includes an upper disk 632 and a lower disk 634, to define the closed loop path 638. As such, the toe ends 651 of the steps 650 are constrained to traverse a closed loop path 638 that corresponds to the shape of the continuous loop formed by flexible member 636. The toe ends 651 are coupled to the flexible member 636 at fixed locations along the path 638. The toe ends 651 may be pivotally coupled to the flexible member 636 to enable the orientation of the user-support surface 652 of the steps 650 relative to the flexible member 636 to vary as the step traverses the closed loop path 638. The first support structure 656-1 may include any suitable structure for pivotally coupling the toe end 651 of the step to the flexible member 636. For example, the first support structures 656-1 may each include a pin 657 rigidly coupled to extend from a respective lateral side of the step 650, e.g., via first mounts 659-1, such that the pins 657 extend substantially transversely to the step 650 (e.g., perpendicular to the depth D direction) toward the left and right upright frame 640 a and 640 b, respectively. The pins 657 may be pivotally received in corresponding couplings fixed to the flexible member 636.

The heel ends 653 of each step 650 may be substantially constrained to move along a closed loop path defined by a track system 670. As such, the second support structures 656-2 may include any suitable structure for rollably or slidably engaging a track. For example, the second support structures 656-2 may include one or more rollers 655-2 rotatably mounted to each side of the step platform 654, e.g., via a mount which may include a shaft that rotatably supports the roller(s) 655-2. The roller(s) 655-2 may be mounted such that their rotation axes is in-plane with the axes of the pins 657. As such, the first and second support structures 656-1 and 656-2 may lie in a same plane 658-1, which may be located below the user-support surface 652 of the step 650. The third support 656-3 may also be configured to engage the track system 670 and may, thus, include any suitable structure for rollably or slidably engaging a track, such as one or more rollers 655-3, which may be mounted to extend from the lateral sides of the step such as via respective mounts 659-3.

The first, second, and third supports 656-1, 656-2, 656-3, respectively, define three different planes of engagement, which are parallel to but offset from one another, as seen e.g., in FIGS. 29B and 30. Each of the first, second, and third supports 656-1, 656-2, 656-3, respectively, engages corresponding components of the drive system 630 that are out of plane. The first support 656-1 defines a first engagement plane 608-1 and as such the component(s) of the drive system 630 that engage the first support 656-1 may lie substantially in the first engagement plane 608-1. The second support 656-2 defines a second engagement plane 608-2 which is offset laterally inward (towards the mid-plane of the stepmill) form the first engagement plane 608-1, and the third support 656-3 defines a third engagement plane 608-3 which is offset laterally inward from the second engagement plane 608-2. As such, the second support 656-2 and the third support 656-3 engage with the drive system 630 at location and/or with components that may lie in planes laterally offset from one another.

With reference now also to FIGS. 28A-B, and FIG. 30, the drive system 630 defines and guides the heel ends 653 of the steps 650 along a path 639 defined by a track system 670. The track system 670 includes one or more track members that provide a support surface for rollably or slidably supporting the second support structures 656-2 of the steps 650 along the desired path. The track system may include a primary track 671, which may include a first (e.g., upper) track 672 that substantially defines the front side 611 of the closed loop path 639, and a second (e.g., lower) track 674 that substantially defines the underside 615 of the closed loop path 639. Each of the first and second tracks 672 and 674, respectively, may be provided by either a single continuous track member or multiple track members operatively arranged to provide the desired track surface of the respective one of the first and second tracks 672 and 674. For example, the first (e.g., upper) track 672 may be provided by a single continuous track member 672-1, which extends substantially the full distance along the front side 611 of the closed loop path 639 from a first track entrance 673-1 to a first track exit 673-2 near the lower disk 634. The heel end 653 of each step 650 may be provided to the first track 672 at the first track entrance 673-1 and may follow the track 672 (e.g., rolling along the length of the track member 672-1) until the heel end 653 reaches the first track exit 673-2 located at the end of the track member 674-1, whereupon the heel end 653 may engage the guide wheel 635.

The second (e.g., lower) track 674 may be provided by one or a plurality of separate track members. In the present example, the second (e.g., lower) track 674 includes a first lower track member 674-1, a second lower track member 674-2, and a third lower track member 674-3, each of which provides a portion of the support or track surface of the second (e.g., lower) track 674. The heel ends 653 of each step 650 are provided to the second track 674 through a second track entrance 675-1 located near the lower disk 634, the steps 650 exiting the second track 674 at the second track exit 675-2 located near the upper disk 632. Two adjacent track members (e.g., two adjacent ones of the lower track members) may have track surfaces that are substantially continuous so as to provide a smooth transition for the heel ends 653 from one track member to another. By continuous, it is meant that the second support (e.g., rollers) of a step traverse a substantially smooth or continuous path as they pass across an interface between two track members. A substantially continuous path (i.e., a path without any substantial discontinuities) may be provided the adjacent track surfaces of two adjacent tracks being substantially co-planar (although not necessarily flat). Co-planar surfaces may be curved surfaces as long as there are no substantial discontinuities between the two surfaces. For example, as shown in FIG. 28B, the first lower track member 674-1 may have a track surface which is substantially co-planar with the track surface of the second lower track member 674-2 allowing the heel end 653 of a step 650 to smoothly transition from the first lower track member 674-1 to the second lower track member 674-2. In some embodiments, a track member may include a ramp at the interface with another track member so as to provide a smooth transition and thus a continuous path as the steps move from one track member to an adjacent track member. The second (e.g., lower) track 674 may define a track exit 675-2, where upon the heel ends 653 of each step 650 is transferred to the first (e.g., upper) track 672 as the step 650 is flipped to the front side 611 of the stepmill 600.

The track system 670 may include a secondary track 681, also referred to as assist track 681, which may include one or more assist track members (e.g., first assist track member 681-1, and second assist track member 681-2). The track member(s) of the secondary track 681 may be suitably arranged for engagement with the third support 656-3 of the steps 650 to intermittently support the steps 650 across discontinuities in the primary track 671 and/or to operatively position the second support 656-2 into engagement with the primary track 671. As such, the secondary track 681 defines a path in the third engagement plane 688-8, which is inwardly offset from the second engagement plane 608-2 in which the primary track 671 resides (see e.g., FIG. 30). The assist track 681 may be a discontinuous track as it may provide support, only intermittently, to a step 650. The secondary (or assist) track 681 may be used to enable the heel ends 653 of the steps 650 to bridge discontinuities, if any, in the primary track 671. The primary track 671 may include discontinuities at location(s) where the second closed loop path 639 crosses the first closed loop path 638, for example on the underside of the paths at location 677-1 and on the front side of the paths at location 677-2. To enable the heel ends 653 of the steps 650 to cross the first closed loop path 638 traversed by the toe end 651, the heel ends 653 of the steps 650 may, be temporarily lifted off the primary track 671 and deposited back on the primary track 671 at a location of the primary track 671 on the opposite side of the first closed loop path 638. As such, the primary track 671 need not physically intersect or cross the first closed loop path 638.

The lifting of the heel ends 653 may be achieved through engagement, at the appropriate time, of the third support 656-3 with a portion of the assist track 681. For example, a first assist track member 681-1 may be positioned between the second and third lower track members 674-2 and 674-3 such that a leading portion of the first assist track member 681-1 overlaps with the second lower track member 674-2 and a trailing portion of the first as member 681-1 overlaps with a portion of the third lower track member 674-3. The first assist track member 681-1 may be operatively positioned vertically above the track surfaces of both the second and third lower track members 674-2 and 674-3 to engage the third support 656-3, which in the present example is vertically above the second support 656-2. The first assist track member 681-1 may define a path (e.g., via its track surface) that inclines away from the second lower track member 674-2 to lift the step 650 off the second lower track member 674-2. As the heel end 653 of a step 650 approaches the entrance 683-1 of the first track assist member 681-1, the third support 656-3 of that step engages the assist track member 681-1 and the heel end 653 of the step is lifted off the primary track as the toe end 651 of the step continues to pull (via the flexible member 636) the step along the travel direction. The heel end 653 is then deposited onto the third lower track member 674-3 to re-engage the primary track 671.

In a similar manner, the assist track 681, and more specifically a second assist track member 681-2 temporarily lifts the heel end 653 of each step 650 to transfer the heel end 653 from the second (e.g., lower) track 674 to the first upper) track 672 at the location 677-2 near the upper disk 632. Six steps 650 are shown in FIGS. 2B and 30 to illustrate various positions of a step 650 as it traverses the closed loop path. The total number and relative position of the steps 650 in various embodiments of the stepmill 600 may not correspond to the arrangement shown as embodiments of the stepmill 600 may include a greater number (e.g., steps, 8 steps, or more) or fewer steps (5 steps or fewer). In various embodiments of the stepmill 600, adjacent steps may be sufficiently spaced apart to ensure that the adjacent steps do not contact or otherwise interfere with one another as they move along their closed loop path. In some embodiments, the plurality of steps (e.g., 5, 6, 7, 8 or more steps) may be equally spaced or distributed along the length of the flexible member 636.

In accordance with some examples, the drive system 630 is configured to flip each step 650 twice along their closed loop path, once at the lower end of the path with the assistance of a guide wheel 635 that supports the heel ends 653 of the steps 650 during the lower transition (e.g., during the flipping of the step), and once at the upper end of the path with the assistance of the secondary track 681 which acts as a step flipper to temporarily lift the heel ends 653 off the primary track and re-position the heel ends on a separate, discontinuous track member of the primary track 671. In some embodiments, one or more auxiliary track members 685 may extend along portions of the primary track 671 to engage the third support 656-3 of a step while the second support 656-2 engages the primary track 671. This may provide a n ore robust coupling of the step 650 to the track system 670.

FIGS. 32A-32D show enlarged views of the upper portion of the stepmill 600 in the view shown in FIG. 28B, with a step 650 shown at different points along the closed loop path to illustrate the operation of the flipper mechanism, implemented here using a secondary (or assist) track 681. In each successive view, starting from FIG. 32A, the step 650 has advanced along its closed loop path along the direction of travel, shown by arrow 601. In a first point along the closed loop path shown in FIGS. 32A, the toe end 651 of the step 650 is just at or nearing the top of the path and the heel end 653 is located at the second exit 675-2 of the second (e.g., lower) track 674. At this point along the path, the third support 656-3 is unsupported (or disengaged) from the drive system 630. As shown, the third support (e.g., roller 655-3) is not in contact with a track but is instead floating. In FIG. 32B, the toe end 651 has advanced along the loop defined by the flexible member 636 (e.g., along the first closed loop path) and the heel end 653 of the step 650 is engaged, via contact between the third support 656-2 and the second track 674, with the drive system 630. As the toe end 651 continues travel around the upper disk 632, the third support 656-3 is operatively positioned for engagement with the secondary track 681, and specifically with the second assist track member 681-2. The track member 681-2 may be angled away from the track member of the second track 674 whereby the heel end 653 of the step 650 may become disengaged from (e.g., lifted off) the primary track 671 as the step 650 continues along the closed loop path (e.g., along direction of travel 601), as shown in FIG. 32C. The secondary (or assist) track 681 acts to support the step 650 as the heel end 653 bridges the discontinuity or gap between track members of the primary track 671 (e.g., lower track member 674-3 and upper track member 672-2). The assist track 681 may aid in operatively positioning the heel end 653 for re-engagement with the primary track 671, such as by positioning the heel end 653 at the first track entrance 673-1. Once re-engaged with the primary track 671, the step 650 may disengage from the secondary track 681, such as by separation of the third support 656-3 from the assist track member 681-2, as shown in FIG. 32D. The step 650 then continues along the closed loop path, along direction of travel 601, with the heel end 653 guided by the primary track 671 and the toe end 851 guided by the flexible member 636 along their respective closed loop paths 639 and 638.

In some embodiments, the stepmill 600 may be incline-adjustable so as to change the angle between a plane defined by the base 621 and a plane defined by the upright frame 640. By changing this angle, also referred to as the incline angle, the incline of the closed loop path of the steps 650 may be varied, resulting in a change in the vertical distance, or step-height H_(S), between adjacent steps 650 when positioned on the front side 811 of the stepmill 600. The stepmill 600 may be configured to be incline-adjustable by supporting components of the drive system 630, such as the one or more flexible members and or one or more tracks that guide the steps, on a moving upright frame 640. Similar to the stepmill 100, the upright frame 640 of stepmill 600 may define a four-bar linkage, e.g., a quadrilateral four-bar linkage. Such a four-bar linkage 41 may include three links movably coupled to a fixed or ground link 48, which may be defined by two fixed points on the frame 620 (see FIG. 26) that remain fixed during incline adjustments. In some embodiments, the ground link 48 may include a physical link such as a rigid member that may be a component of the base 621 or other frame member parallel to the base 621. The moving links may form a quadrilateral four-bar linkage with the ground link 48. The moving links may include a first link 42 pivotally coupled to a first end of the ground link 48, a second link 44 pivotally coupled to a second, opposite end of the ground link 48, and a third link 46 pivotally coupled to both the first and second links 42 and 44. The third link 46 connects the two primary moving links (i.e., the first link 42 and the second link 44) and may thus be referred to as a coupler link. In some embodiments multiple coupler links, all parallel to one another and the ground link 48 and provided at different longitudinal locations along the links 42 and 44, may be used to connect the first and second links 42 and 44, which may enhance the stability of the four-bar linkage 41. As previously described, the ground link 48 may remain in a fixed position relative to the base 621 while the first, second, and third moving links 42, 44, and 46, respectively, move relative to the ground link 48 to adjust the incline angle of the stepmill 600. Components of the drive system 630 may be operatively coupled to frame members that define the four-bar linkage 41 such that the relative positions of components of the drive system can be adjusted to effect an adjustment to the incline of the closed loop path and correspondingly and adjustment to the step-height H_(S). For example, the upper and lower disks 632 and 634 may be positioned at opposite ends of the second moving link 44, in some cases with the rotational axes of the upper and lower disks coinciding with the respective pivot axes A₂ and A₄ of the second link 44. The ground link 48 may be defined by the distance between the rotating axis of the lower disk 634 and the rotation axis of the guide wheel 635. Components of the primary track 671, and more specifically the first (e.g., upper) track 672 may extend along the length of the first link 42. Any suitable arrangement of the various components of the drive system 630 with respect to members of the upright frame 640 may be used to construct a four-bar kinematic chain to enable the relative repositioning of the components of the drive system 630 during incline adjustment.

In embodiments in which the stepmill 600 is incline adjustable, one or more track members of the track system 670 may need to move relative to one another without creating discontinuities in the track surfaces or path provided by the multiple track members. In some such examples, two adjacent track members may overlap at least partially to allow one of the track members to be repositioned without introducing a gap or discontinuity at the interface 678 of the two track members. For example, as the stepmill 600 is adjusted from a first inclined position (as shown in FIG. 33A) to a second inclined position (as shown in FIG. 33B), one track member (e.g., second lower track member 674-2) may move relative to another track member (e.g., first track member 674-1). The two track members may overlap at the interface between the two track such that as one of the two track members (e.g., the second lower track member 674-2) moves relative to the other (e.g., the first lower track member 674-1), the overlapping portions may provide a continuous path for the step. In some embodiments, the overlapping portions of the track may be slidably engaged such that the moving track member slides over a portion of the non-moving track member to increase the length of the closed loop path at that location, as may be needed in an increased incline angle.

In some embodiments, the movement of the steps 650 may be resisted by any suitable resistance mechanism 698. In some embodiments, the stepmill 600 may be operable in a powered (or power-assist) mode in which the movement of the steps is driven or powered by a power source, such as an electrical, hydraulic or other type of motor, so as to set a speed (or cadence) for the user to exercise to. In some embodiments, the movement of the steps along the closed loop path may be driven solely by user-applied force(s) and/or gravity. Referring to FIG. 34, the resistance mechanism 698 may include a brake disk 699 rotatably coupled to the frame 620 (e.g., to the base 621 or elsewhere on the frame 620). The brake disk 699 may be operatively associated with a brake 697, for example a friction brake or a magnetic brake. The rotation of the components of the drive system 630 (e.g., the rotation of the one or more guide disks) may be coupled to the resistance mechanism 698 via a transmission assembly 690. The transmission assembly 690 may include one or more stages that coupled the rotation of the drive system 30 to the brake disk 699 such that this rotation can be resisted by an appropriate retarding force (e.g., a frictional, magnetic, and/or air-based, resistance). As shown in FIG. 34, the transmission assembly 690 may include a first stage 691-1 which includes a first transmission disk 692 and a corresponding first transmission member 694, which couple the rotation of the shaft of one of the guide disk to a second stage 691-2 of the transmission assembly 690. The second stage 691-2 may include a second transmission disk 693 and a corresponding second transmission member 695, which couple the rotation from the first stage 691-1 to the brake disk 699. The transmission stages may be implemented using a chain drive (e.g., a combination of sprockets and chains), a belt drive (e.g., a combination of drums or pulleys and belts), any other suitable combination of components. In some embodiments, one or more tensioners 696-1 and 696-2 may be used to ensure that the transmission members are held at appropriate tension to transmit rotation from one component to the next.

The foregoing description has broad application. The discussion of any embodiment is meant only to be explanatory and is not intended to suggest that the scope of the disclosure, including the claims, is limited to these examples. In other words, while illustrative embodiments of the disclosure have been described in detail herein, the inventive concepts may be otherwise variously embodied and employed, and the appended claims are intended to be construed to include such variations, except as limited by the prior art.

The foregoing discussion has been presented for purposes of illustration and description and is not intended to limit the disclosure to the form or forms disclosed herein. For example, various features of the disclosure are grouped together in one or more aspects, embodiments, or configurations for the purpose of streamlining the disclosure. However, various features of the certain aspects, embodiments, or configurations of the disclosure may be combined in alternate aspects, embodiments, or configurations. Moreover, the following claims are hereby incorporated into this Detailed Description by this reference, with each claim standing on its own as a separate embodiment of the present disclosure.

All directional references (e.g., proximal, distal, upper, lower, upward, downward, left, right, lateral, longitudinal, front, back, top, bottom, above, below, vertical, horizontal, radial, axial, clockwise, and counterclockwise) are only used for illustration purposes to aid the readers understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and may include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other, unless so stated. Identification references (e.g., primary, secondary, first, second, third, fourth, etc.) are not intended to connote importance or priority, but are used to distinguish one feature from another. The drawings are for purposes of illustration only and the dimensions, positions, order and relative sizes reflected in the drawings attached hereto may not be to scale or may vary in other embodiments. 

What is claimed is:
 1. A stair climbing machine comprising: a frame including a base and an upright frame movably coupled to the base; a plurality of steps movably coupled to the upright frame to move in a closed loop path; a lift mechanism operatively coupled to the upright frame to selectively change a position of the upright frame relative to the base to change a step-height of the plurality of steps.
 2. The stair climbing machine of claim 1, wherein the upright frame comprises a left frame portion and a right frame portion and where the steps are positioned between the left and right frame portions, wherein each of the left and right frame portions define a respective four-bar linkage.
 3. The stair climbing machine of claim 2, wherein the four-bar linkage comprises first, second, and third links movably coupled to the base and a fourth link that remains fixed to the base during changes in the position of the upright frame.
 4. The stair climbing machine of claim 2, wherein each step has a heel end and a toe end, and wherein the plurality of steps are coupled to the upright frame via a drive assembly configured to constrain the movement of the toe ends of the steps along a first closed loop path and the movement of the heel ends of the steps along e second closed loop path having a different shape than a shape of the first closed loop path.
 5. The stair climbing machine of claim 4, wherein the toe ends of the steps a coupled to one or more first flexible members routed in a first continuous loop around a set of first guide disks, and where the heel ends of the steps are coupled to one or more second flexible members routed in a second continuous loop around a set of second guide disks.
 6. The stair climbing machine of claim 5, wherein each of the steps is configured to bend around one or more of the first and second guide disks.
 7. The stair climbing machine of claim 6, wherein each step comprises plurality of slats operatively coupled together to support a user's foot when provided in a flat configuration, wherein adjacent slats are configured to pivot relative to one another about an axis parallel with a length of the slats to allow the step to bend around the one or more of the first and second guide disks.
 8. The stair climbing machine of claim 1, wherein the upright frame is selectively adjustable to any of a plurality of inclined angles including art incline angle of about 55 degrees.
 9. The stair climbing machine of claim 1, wherein the upright frame is selectively adjustable to an inclined angle of about zero degrees reducing the step-height to about zero.
 10. The stair climbing machine of claim 2, wherein the respective four-bar linkages defined by the left and right frame portions are primary four-bar linkages, the stair climbing machine further comprising a handlebar assembly that defines left and right secondary four-bar linkages associated with a respective one of the left and right frame portions, wherein each of the secondary four-bar linkages is operatively coupled to the respective primary four-bar linkage whereby each of the secondary four-bar linkages moves as a result of the movement of the respective primary four-bar linkage.
 11. The stair climbing machine of claim 1, wherein each of the plurality of steps comprises a monolithic support platform having a user-supporting side and an underside located opposite the user-supporting side, wherein the closed loop path of the steps has a front side and a rear side, and wherein the steps are oriented such that the user-supporting side of the steps is generally oriented towards a user, when using the stair climbing machine, when the steps are traversing the rear side of the closed loop path.
 12. The stair climbing machine of claim 1, further comprising a step flipper located near an upper side of the closed loop path, the step flipper pivoting each step approaching the upper side of the closed loop path in a direction opposite a direction of travel of the steps along the closed loop path.
 13. The stair climbing machine of claim 1, wherein each step has a heel end and a toe end that move along respective heel end and toe end paths to define respective closed loop paths of the steps, and wherein one of the heel ends or toe ends of the steps is constrained along its respective closed loop path by a flexible member while the other one of the heel ends or toe ends of the steps is constrained along its respective closed loop path by a track system, wherein the heel end of each step moves along a path defined by the track system, and wherein each step is further intermittently supported at a location between the toe end and the heel end of the step.
 14. The stair climbing machine claim 1, further comprising a resistance mechanism configured to adjustably resist the movement of the steps along the closed loop path.
 15. A stair climbing machine comprising: a frame comprising a base and an upright frame; a plurality of steps movably coupled to the upright frame to move in a closed loop path, wherein the plurality of steps are spaced apart from one another such that individual steps do not contact one another as the steps move in the closed loop path, and wherein each of the plurality of steps comprises a supporting platform provided by a plurality of individual slats pivotally connected to one another to allow the step to transition, while moving along the closed loop path, between a flat configuration in which user-supporting surfaces of the slats are substantially co-planar and a bent configuration in which the user-supporting surfaces of at least two adjacent the slats are pivoted away from one another.
 16. A stair climbing machine comprising: a base; first and second upright frames coupled to opposite sides of the base; a plurality of steps positioned in a space defined between the first and second upright frames and movably coupled to the first and second upright frames to move in a closed loop within the space, wherein each step has a toe end constrained to move along a first closed loop path and a heel end constrained to move along a second closed loop path different from the first closed loop path and which crosses the first closed loop path, wherein the first closed loop path is defined by at least one flexible member routed around and engaged with a corresponding plurality of rotating disks, and wherein the second closed loop path is defined by a track system.
 17. The stair climbing machine of claim 16, wherein each step has a first and second lateral side extending between the toe end and the heel end of each step, wherein each step comprises a first support extending from each of the first and second lateral sides that couples the toe end of the step to a respective flexible member, and a second support extending from each of the first and second lateral sides that operatively engages the heel end of the step to a respective side of the track system, wherein the step further comprises a third support extending from each of the first and second lateral sides that intermittently engages at least one track member of the respective side of the track system.
 18. The stair climbing machine of claim 17, wherein a secondary track is positioned to temporarily engage the third support of each step to support the step while the heel end of the step traverses a discontinuity in a track.
 19. The stair climbing machine of claim 16, wherein the first and second upright frames are movably coupled to the base for selectively changing the closed loop traversed by the steps, wherein each of the first and second upright frames define a four-bar linkage, and wherein a fixed link of the four-bar linkage is arranged parallel to the base.
 20. The stair climbing machine of claim 19, further comprising a handlebar assembly that defines a secondary four-bar linkage, and wherein a fixed link of the secondary four-bar linkage is defined by an upright support of the handlebar assembly. 